Editing ZX Spectrum

{{Short description|1982 home computer}}
{{Good article}}
{{Use dmy dates|date=May 2024}}
{{Infobox computing device
| logo = Sinclair ZX Spectrum-02b.svg
| image = ZXSpectrum48k.jpg
| caption = Issue 2 1982 model
| type = [[Home computer]]
| developer = [[Sinclair Research]]
| generation = [[8-bit computing|8-bit]]
| release date = {{Video game release|UK|23 April 1982<ref name="BT">{{cite web |last1=Lewis |first1=Rhys |title=April 23, 1982: ZX Spectrum brings affordable&nbsp;– and colourful&nbsp;– computing into Britain's homes |url=https://home.bt.com/news/world-news/april-23-1982-zx-spectrum-brings-affordable-and-colourful-computing-into-britains-homes-11363977137042 |publisher=[[British Telecom]] |access-date=4 April 2021 |archive-url=https://web.archive.org/web/20160430023322/http://home.bt.com/news/world-news/april-23-1982-zx-spectrum-brings-affordable-and-colourful-computing-into-britains-homes-11363977137042 |archive-date=30 April 2016 |location=London |date=23 April 2016}}</ref>|US|{{start date|1983}}|EU|{{start date|1985}}}}
| discontinued = 1992<ref name="bbclegacy">{{cite web |title=How the Spectrum began a revolution |url=http://news.bbc.co.uk/2/hi/technology/6572711.stm |publisher=[[BBC]] |access-date=4 April 2021 |archive-url=https://web.archive.org/web/20210126180152/http://news.bbc.co.uk/2/hi/technology/6572711.stm |archive-date=26 January 2021 |date=23 April 2007}}</ref>
| units sold = 5 million{{sfn|Mott|2000|p=76}}
| price = UK: [[Pound sterling|£]]125 (16&nbsp;[[Kilobyte|KB]]) ({{Inflation|UK|125|1982|fmt=eq|cursign=£}}) / £175 (48&nbsp;KB) ({{Inflation|UK|175|1982|fmt=eq|cursign=£}}) ,{{sfn|Leigh|2018|p=69}} US: [[United States dollar|$]]200, ESP: [[Spanish peseta|Pta]]44,250
| media = [[Compact Cassette (data)|Compact Cassette]], [[ZX Microdrive]], [[Floppy disk variants|3-inch floppy disk]] on Spectrum +3
| cpu = [[Z80A]] (or equivalent)
| memory = 16&nbsp;[[kibibyte|KB]]&nbsp;/ 48&nbsp;KB&nbsp;/ 128&nbsp;KB<br />''(IEC: [[Kibibyte|KiB]])''
| predecessor = [[ZX81]]
| successor = [[Sinclair QL|QL]], [[Sinclair PC200]]
| os = [[Sinclair BASIC]]
| CPUspeed = 3.5&nbsp;MHz
| graphics = [[Gate array|ULA]]
| display = [[PAL]] [[RF modulator]] out<br>256 × 192, 15 colours
| sound = Beeper, [[AY-3-8912]] (128K models)
}}

The '''ZX Spectrum''' ({{IPAc-en|uk|z|ɛ|d|_|ɛ|k|s}}) is an [[8-bit computing|8-bit]] [[home computer]] developed and marketed by [[Sinclair Research]]. One of the most influential computers ever made and one of the all-time bestselling British computers, over five million units were sold. It was released in the United Kingdom on 23 April 1982, and around the world in the following years, most notably in Europe and the United States.

The machine was designed by English entrepreneur and inventor Sir [[Clive Sinclair]] and his small team in [[Cambridge]], and was manufactured in [[Dundee]], Scotland by [[Timex Corporation]].<ref name="Day" /> It was made to be small, simple, and most importantly inexpensive, with as few components as possible. The addendum "Spectrum" was chosen to highlight the machine's colour display, which differed from the black-and-white display of its predecessor, the [[ZX81]]. [[Rick Dickinson]] designed its distinctive case, rainbow motif, and [[chiclet keyboard|rubber keyboard]]. Video output is transmitted to a television set rather than a dedicated [[computer monitor|monitor]], while [[application software]] is loaded and saved onto [[compact audio cassette]]s.

The ZX Spectrum was initially distributed by mail order, but after severe backlogs it was sold through [[High Street]] chains in the United Kingdom. It was released in the US as the [[Timex Sinclair 2068]] in 1983, and in some parts of Europe as the [[Timex Computer 2048]]. Ultimately the Spectrum was released as seven  models, ranging from the entry level with 16&nbsp;[[Kilobyte|KB]] RAM released in 1982 to the ZX&nbsp;Spectrum&nbsp;+3 with 128&nbsp;KB RAM and built-in [[floppy disk]] drive in 1987. Throughout its life, the machine primarily competed with the [[Commodore&nbsp;64]], [[BBC&nbsp;Micro]], [[Dragon&nbsp;32]], and the [[Amstrad&nbsp;CPC]] range. Over 24,000 software products were released for the ZX Spectrum.<ref name=BT/>

The Spectrum played a pivotal role in the early [[History of personal computers|history of personal computing]] and [[history of video games|video gaming]], leaving a legacy that influenced generations. Its introduction led to a boom in companies producing software and [[computer hardware|hardware]], the effects of which are still seen. It was among the first home computers aimed at a mainstream UK audience, with some crediting it for launching the British information technology industry. The Spectrum was Britain's top-selling computer until the [[Amstrad PCW]] surpassed it in the 1990s.<ref name="backlash">{{cite web |last1=Cellan-Jones |first1=Rory |title=The Spectrum, the Pi - and the coding backlash |url=https://www.bbc.co.uk/news/technology-17811925 |website=BBC News |access-date=30 June 2021 |date=23 April 2012 |archive-date=9 July 2021 |archive-url=https://web.archive.org/web/20210709182844/https://www.bbc.co.uk/news/technology-17811925 |url-status=live }}</ref><ref name="typewriter">{{cite news |last=Moran |first=Joe |date=2015-08-28 |url=https://www.theguardian.com/books/2015/aug/28/how-amstrad-word-processor-encouraged-writers-use-computers |title=Typewriter, you're fired! How writers learned to love the computer |work=[[The Guardian]] |page=20 |archiveurl=https://web.archive.org/web/20150906135613/https://www.theguardian.com/books/2015/aug/28/how-amstrad-word-processor-encouraged-writers-use-computers |archivedate=2015-09-06}}</ref><ref name="slice">{{cite journal |last=Crookes |first=David |date=2016-03-10 |url=https://archive.org/details/Micro-Mart |title=Fancy a Fresh Slice of Pi? | journal=[[Micro Mart]] |publisher=[[Dennis Publishing]] |issue=1404 |pages=8–10, 12, 14, 16 |via=the Internet Archive}} {{ProQuest|1787168972}}.</ref> It was discontinued in 1992.

== History ==
[[File:Sir Clive Sinclair on X-Bike Prototype.jpg|thumb|left|Sir [[Clive Sinclair]] riding an X-Bike prototype in 1990]]

The ZX Spectrum was conceived and designed by engineers at Sinclair Research, founded by English entrepreneur and inventor [[Clive Sinclair]], who was well known for his eccentricity and pioneering ethic.<ref name="bizhistory">{{cite web |last1=Oliver |first1=Phillip |title=ZX Spectrum: An enduring legacy |url=https://www.gamesindustry.biz/zx-spectrum-an-enduring-legacy |website=GamesIndustry.biz |publisher=[[Gamer Network]] |access-date=1 October 2023 |archive-url=https://web.archive.org/web/20221104151132/https://www.gamesindustry.biz/zx-spectrum-an-enduring-legacy |archive-date=4 November 2022 |location=[[Brighton]] |language=en |date=26 October 2017}}</ref> On 25 July 1961, three years after passing his [[GCE Advanced Level (United Kingdom)|A-level]]s, he founded [[Sinclair Radionics]] Ltd as a vehicle to advertise his inventions and buy components.{{sfn|Dale|1985|p=21}} In 1972, Sinclair had competed with [[Texas Instruments]] to produce the world's first [[pocket calculator]], the [[Sinclair Executive]].<ref name=newyork>{{cite web |last1=Bailey |first1=Elizabeth |title=Inventor; trying again in consumer electronics |url=https://www.nytimes.com/1981/04/12/business/inventor-trying-again-in-consumer-electronics.html |work=[[The New York Times]] |access-date=1 October 2023 |archive-url=https://web.archive.org/web/20230516222227/https://www.nytimes.com/1981/04/12/business/inventor-trying-again-in-consumer-electronics.html |archive-date=16 May 2023 |location=New York City |date=12 April 1981}}</ref> By the mid 1970s, Sinclair Radionics was producing handheld electronic calculators, miniature televisions, and the ill-fated digital [[Black Watch (wristwatch)|Black Watch]] wristwatch.{{sfn|Leigh|2022|pp=80-81}} Due to financial losses, Sinclair sought investors from the [[National Enterprise Board]] (NEB), who had bought a 43% interest in the company and streamlined his product line. Sinclair's relationship with the NEB had worsened, however, and by 1979 it opted to break up Sinclair Radionics entirely,{{sfn|Kean|1985b|p=126}} selling off its television division to [[Binatone]] and its calculator division to ESL Bristol.{{sfn|Dale|1985|pp=77-78}}

After incurring a £7 million investment loss, Sinclair was given a [[golden handshake]] and an estimated £10,000 severance package.<ref name=newyork/><ref>{{cite web |title=Sir Clive Sinclair obituary |url=https://www.thetimes.com/uk/obituaries/article/sir-clive-sinclair-obituary-jjgjq296k |work=[[The Times]] |access-date=1 October 2023  |location=London |language=en |date=1 October 2023 |url-status=live |archive-url= https://archive.today/20210916203447/https://www.thetimes.co.uk/article/sir-clive-sinclair-obituary-jjgjq296k |archive-date= 16 September 2021  }}</ref> He had a former employee, [[Christopher Curry (businessman)|Christopher Curry]], establish a "corporate lifeboat" company named Science of Cambridge Ltd, in July 1977, called such as they were located near the [[University of Cambridge]].{{sfn|Dale|1985|p=89}} By this time inexpensive [[microprocessor]]s had started appearing on the market, which prompted Sinclair to start producing the [[MK14]], a [[electronic kit|computer teaching kit]] which sold well at a very low price.{{sfn|Dale|1985|p=91}} Encouraged by this success, Sinclair renamed his company to [[Sinclair Research]], and started looking to manufacture personal computers. Keeping the cost low was essential for Sinclair to avoid his products from becoming outpriced by American or Japanese equivalents as had happened to several of the previous Sinclair Radionics products.<ref name=newyork/> On 29 January 1980, the [[ZX80]] home computer was launched to immediate popularity; notable for being one of the first computers available in the United Kingdom for less than £100.{{sfn|Laurie|1981|p=113}}{{sfn|Hayes|1981|p=119}} The company conducted no market research whatsoever prior to the launch of the ZX80; according to Sinclair, he "simply had a hunch" that the public was sufficiently interested to make such a project feasible and went ahead with ordering 100,000 sets of parts so that he could launch at high volume.<ref name="FT-noresearch">{{cite news| title = The precarious balance between research, fashion and price| last = Lorenz | first = Christopher| newspaper = [[Financial Times]]|location=London| page = 18| date = 15 April 1982}}</ref>

On 5 March 1981, the [[ZX81]] was launched worldwide to immense success with more than 1.5 million units sold,<ref name="Sinclair-Research">{{cite web| title = Sinclair ZX8| publisher = Sinclair Research| url = http://www.sinclairzx.com/about-us.html#12 | url-status = dead| archive-url = https://web.archive.org/web/20141214131822/http://www.sinclairzx.com/about-us.html#12| access-date = 5 January 2011 | archive-date = 14 December 2014}}</ref> 60% of which was outside Britain.{{sfn|Clarke|1982|p=390}} According to [[Ben Rosen]], by pricing the ZX81 so low, the company had "opened up a completely new market among people who had never previously considered owning a computer".{{sfn|Engineering Today|1982|pp=20–23}} After its release, computing in Britain became an activity for the general public rather than the preserve of office workers and hobbyists. The ZX81's commercial success made Sinclair Research one of Britain's leading computer manufacturers, with Sinclair himself reportedly "amused and gratified" by the attention the machine received.{{sfn|Hayman|1982|p=23}}

=== Development ===
[[File:ZX Spectrum concept.jpg|thumb|An original concept sketch of the ZX Spectrum, depicting an angular and wedge-like form similar to its predecessor, the [[ZX81]] ]]

Development of the ZX Spectrum began in September 1981, a few months after the release of the ZX81. Sinclair resolved to make his own products obsolete before his rivals developed the products that would do so. Parts of designs from the ZX80 and ZX81 were reused to ensure a speedy and cost-effective manufacturing process. The team consisted of 20 engineers housed in a small office at 6 [[King's Parade]], Cambridge.<ref name="edgehistory">{{cite magazine |last1=Brown |first1=Nathan |title=The making of the ZX Spectrum |url=http://www.edge-online.com/features/making-zx-spectrum/ |magazine=[[Edge (magazine)|Edge]] |publisher=[[Future plc]] |access-date=4 April 2021 |archive-url=https://web.archive.org/web/20120425035159/http://www.edge-online.com/features/making-zx-spectrum/ |archive-date=25 April 2012 |location=[[Bath, Somerset|Bath]] |date=23 April 2012}}</ref> During early production, the machine was known as the ZX81 Colour or the ZX82 to highlight the machine's colour display, which differed from the black and white of its predecessors. The addendum "Spectrum" was added later on, to emphasise its 15-colour palette.{{sfn|Leigh|2018|p=68}} Aside from a new [[crystal oscillator]] and extra chips to add additional [[kilobyte]]s of memory,{{sfn|Adams|1982|p=14}} the ZX Spectrum was intended to be, as quoted by Sinclair's marketing manager, essentially a "ZX81 with colour".<ref name=edgehistory/> According to Sinclair, the team also wanted to combine the ZX81's separate [[random-access memory]] sections for audio and video into a single bank.<ref name="registerlegacy">{{cite web |last1=Speed |first1=Richard |title=Sinclair's 8-bit home computer, ZX Spectrum, turns 40 |url=https://www.theregister.com/2022/04/22/spectrum_at_40/ |website=The Register |publisher=Situation Publishing |access-date=2 October 2023 |archive-url=https://web.archive.org/web/20230526232039/https://www.theregister.com/2022/04/22/spectrum_at_40/ |archive-date=26 May 2023 |location=London |language=en |date=22 April 2022}}</ref>

Chief engineer [[Richard Altwasser]] was responsible for the ZX Spectrum's hardware design. His main contribution was the design of the semi-custom [[Gate array|uncommitted logic array]] (ULA) integrated circuit, which integrated, on a single chip, the essential hardware functions. Altwasser designed a graphics mode that required less than 7 kilobytes of memory and implemented it on the ULA. Vickers wrote most of the ROM code. Lengthy discussions between Altwasser and Sinclair engineers resulted in a broad agreement that the ZX Spectrum must have high-resolution graphics, 16 kilobytes of memory, an improved [[Cassette tape#data|cassette interface]], and an impressive colour palette.{{sfn|Gore|1982|p=38}} To achieve this, the team had to divorce the [[central processing unit]] (CPU) away from the main display to enable it to work at full efficiency – a method which contrasted with the ZX81's integrated CPU.{{sfn|Gore|1982|p=38}} The inclusion of colour to the display proved a major obstacle to the engineers. A [[Teletext]]-like approach was briefly considered, in which each line of text would have colour-change codes inserted into it. However, this was ruled out, as it was deemed unsuitable for high-resolution graphs or diagrams that involved multiple colour changes. Altwasser devised the idea of allocating a [[BIOS color attributes|colour attribute]] to each character position on the screen. This ultimately used eight [[bit]]s of memory for each character position; three bits to provide any one of eight foreground colours and three bits for the eight [[Web colors|background colours]], one bit for extra brightness and one bit for flashing. Overall, the system took up slightly less than 7 kilobytes of memory, leaving an additional 9 kilobytes to write programs&nbsp;– a figure that pleased the team.{{sfn|Gore|1982|pp=38-39}}

Much of the firmware was written by computer scientist [[Steve Vickers (computer scientist)|Steve Vickers]] from Nine Tiles,<ref name="registerlegacy"/> who compiled all control routines to produce the [[Sinclair BASIC]] interpreter, a custom variant of the general purpose [[BASIC]] programming language. Making a custom interpreter made it possible to fit all of its functionality into a very small amount of [[read-only memory]] (ROM).{{sfn|Adams|1982|p=14}} The development process of the software was marked by disagreements between Nine Tiles and Sinclair Research. Sinclair placed an emphasis on expediting the release of the Spectrum, primarily by minimising alterations in the software from the ZX81, which had in turn been based on the ZX80's software. The software architecture of the ZX80, however, had been tailored for a severely constrained memory system, and in Nine Tiles' opinion was unsuitable for the enhanced processing demands of the ZX Spectrum. Sinclair favoured solving this with expansion modules on the existing framework like with the ZX81, which Nine Tiles disagreed with. Ultimately, both designs were developed, but Vickers and Nine Tiles were unable to finish their version before the launch of the Spectrum and it was not used.{{sfn|Adamson|Kennedy|1986|pp=84-88}}

[[File:Rick Dickinson.jpg|thumb|left|Designer [[Rick Dickinson]] in the [[Sinclair Research]] Cambridge office in 1983]]
The distinctive case and colourful design of the ZX Spectrum was the creation of [[Rick Dickinson]], a young British industrial designer who had been hired by Sinclair to design the ZX81. Dickinson was tasked to design a sleeker and more "marketable" appearance to the new machine, whilst ensuring all 192 BASIC functions could fit onto 40 physical keys.<ref name=edgehistory/> Early sketches from August 1981 showed the case was to be more angular and wedge-like, in similar vein to an upgraded ZX81 model. Dickinson later settled on a flatter design with a raised rear section and rounded sides in order to depict the machine as "more advanced" as opposed to a mere upgrade. In drawing up potential logos, Dickinson proposed a series of different logotypes which all featured rainbow slashes across the keyboard.<ref name=registerhistory/>

The design of the Spectrum's [[Chiclet keyboard|rubber keyboard]] was simplified from several hundred components to a conventional moving keyboard down to "four to five" moving parts using a new technology.<ref name="bbc30">{{cite web |last1=Kelion |first1=Leo |title=ZX Spectrum's chief designers reunited 30 years on |url=https://www.bbc.co.uk/news/technology-17776666 |website=[[BBC News]] |publisher=[[BBC]] |access-date=2 October 2023 |archive-url=https://web.archive.org/web/20230418150809/https://www.bbc.co.uk/news/technology-17776666 |archive-date=18 April 2023 |location=London |date=19 April 2012}}</ref> The keyboard was still undergoing changes as late as February 1982; some sketches included a roundel-on-square key design which was later featured on the later Spectrum+ model.<ref name=registerhistory/> Dickinson recalled in 2007 that "everything was cost driven" and that the minimalist, [[Bauhaus]] approach to the Spectrum gave it an elegant yet "[non] revolutionary" form.<ref name=bbclegacy/> The drawing board on which Dickinson designed the ZX Spectrum is now on display in the [[Science Museum, London|Science Museum]] in London.<ref>{{cite web |title=Sinclair Spectrum designer Rick Dickinson dies in US |url=https://www.bbc.co.uk/news/technology-43907248 |website=[[BBC News]] |publisher=[[BBC]] |archive-url=https://web.archive.org/web/20230930220700/https://www.bbc.co.uk/news/technology-43907248 |archive-date=30 September 2023 |location=London |date=26 April 2018}}</ref><ref>{{cite web |title=Alpia drawing board - Science Museum Group Collection |url=https://collection.sciencemuseumgroup.org.uk/objects/co8087251/alpia-drawing-board-used-by-rick-dickinson-to-des-drawing-board |publisher=The Science Museum Group |access-date=9 October 2023 |archive-url=https://web.archive.org/web/20221129031620/https://collection.sciencemuseumgroup.org.uk/objects/co8087251/alpia-drawing-board-used-by-rick-dickinson-to-des-drawing-board |archive-date=29 November 2022 |location=London |language=en}}</ref>

The need for an improved cassette interface was apparent from the number of complaints received from ZX81 users, who encountered problems when trying to save and load programs.{{sfn|Gore|1982|p=39}} To increase the data transfer speed, the team significantly decreased the length of tones that represent binary data.{{sfn|Gore|1982|p=39}} To increase the reliability, a leading period of [[pure tone|constant tone]] was introduced, which allowed the cassette recorder's [[automatic gain control]] to settle itself down, eliminating hisses on the tape.{{sfn|Gore|1982|p=39}} A [[Schmitt trigger]] was added inside the ULA to reduce noise of the received signal.{{sfn|Gore|1982|p=39}} Originally, the team aimed for data transfer speed of 1000 [[baud]], but succeeded in getting it to work at a considerably faster 1500 baud.{{sfn|Gore|1982|p=39}} Unlike the ZX81, the Spectrum was able to maintain its display during loading and saving operations, and programmers took advantage of this to show a [[splash screen]] whilst loading took place in the background.

As with the ZX81, the ZX Spectrum was manufactured in [[Dundee]], Scotland, by [[Timex Group USA|Timex Corporation]] at the company's [[Dryburgh, Dundee district|Dryburgh]] factory.<ref name="Day">{{cite news|last1=Day|first1=Peter|title=How Dundee became a computer games centre|work=[[BBC News]]|location=London|date=9 September 2014|url=https://www.bbc.co.uk/news/business-29122873|access-date=12 November 2016|url-status=live|archive-url=https://web.archive.org/web/20161009014928/http://www.bbc.co.uk/news/business-29122873|archive-date=9 October 2016}}</ref><ref>{{cite web |title=ZX Spectrum Computer and associated game cassettes |url=https://www.themcmanus-dundee.gov.uk/content/collections/database/zx-spectrum-computer-and-associated-game-cassettes |website=The McManus |publisher=Dundee Art Gallery |access-date=3 October 2023 |archive-url=https://web.archive.org/web/20231003134524/https://www.themcmanus-dundee.gov.uk/content/collections/database/zx-spectrum-computer-and-associated-game-cassettes |archive-date=3 October 2023 |location=[[Dundee]] |language=English |date=20 January 2012}}</ref> Prior to the manufacture of the ZX81, however, Timex had little experience in assembling electronics and had not originally been an obvious choice of manufacturing subcontractor. It was a well-established manufacturer of mechanical watches but was facing a crisis at the beginning of the 1980s; profits had dwindled to virtually zero as the market for watches stagnated in the face of competition from the [[Watch#Digital|digital]] and [[Quartz clock|quartz watches]]. Recognising the trend, Timex's director, [[Fredrik Olsen|Fred Olsen]], determined that the company would diversify into other areas and signed a contract with Sinclair.{{sfn|Adamson|Kennedy|1986|p=94}}

=== Launch ===
The ZX Spectrum was officially revealed before journalists by Sinclair at the [[Hyatt Regency London – The Churchill|Churchill Hotel]] in [[Marylebone]], London, on 23 April 1982.<ref name="registerhistory">{{cite web |last1=Smith |first1=Tony |title=Happy 30th Birthday, Sinclair ZX Spectrum |url=https://www.theregister.com/2012/04/23/retro_week_sinclair_zx_spectrum_at_30?page=1 |website=The Register |access-date=2 October 2023 |archive-url=https://web.archive.org/web/20231002185823/https://www.theregister.com/2012/04/23/retro_week_sinclair_zx_spectrum_at_30?page=1 |archive-date=2 October 2023 |language=en |date=23 April 2012|url-status=live}}</ref><ref name="autogenerated1">{{Cite news | last = Warman | first = Matt | date = 23 April 2012 | title = ZX Spectrum at 30: the computer that started a revolution | newspaper = [[The Daily Telegraph]] | url = https://www.telegraph.co.uk/technology/news/9220468/ZX-Spectrum-at-30-the-computer-that-started-a-revolution.html | location = London | archive-url = https://web.archive.org/web/20130308205705/http://www.telegraph.co.uk/technology/news/9220468/ZX-Spectrum-at-30-the-computer-that-started-a-revolution.html | archive-date = 8 March 2013 | url-status = live | access-date = 31 March 2015 | quote = It was the computer that introduced a generation to video gaming, helped to earn Sir Clive Sinclair a knighthood and even made programming cool: the ZX Spectrum has a lot to answer for. }}</ref> Later that week, the machine was officially presented in a "blaze of publicity" at the [[Earl's Court]] Computer Show in London,<ref>{{cite web |title=ZX Spectrum profile |url=https://www.retrogamer.net/profiles/hardware/zx-spectrum-hardware-profile/ |website=[[Retro Gamer]] |publisher=[[Future plc]] |access-date=3 October 2023 |archive-url=https://web.archive.org/web/20221215164112/https://www.retrogamer.net/profiles/hardware/zx-spectrum-hardware-profile/ |archive-date=15 December 2022 |location=[[Bath, Somerset|Bath]] |date=4 December 2013}}</ref>{{sfn|Adams|1982|p=52}} and the ZX Microfair in [[Manchester]].{{sfn|Clark|1982|p=4}} The ZX Spectrum was launched with two models: a 16KB 'basic' version, and an enhanced 48KB variant.{{sfn|Leigh|2018|p=69}} The former model had an undercutting price of £125, significantly lower than its main competitor the [[BBC Micro]], whilst the latter model's price of £175 was comparable to a third of an [[Apple II]] computer.{{sfn|Clark|1982|p=14}}{{sfn|Kean|1985b|p=127}} Upon release, the keyboard surprised many users due to its use of rubber keys, described as offering the feel of "dead flesh".<ref name=registerhistory/><ref name="telegraph">{{cite web |title=Sir Clive Sinclair, inventor of an early pocket calculator who transformed the home-computing market but came unstuck with the infamous C5 – obituary |url=https://www.telegraph.co.uk/obituaries/2021/09/16/sir-clive-sinclair-inventor-early-pocket-calculator-transformed/ |publisher=[[The Daily Telegraph|The Telegraph]] |access-date=3 October 2023 |archive-url=https://web.archive.org/web/20221118063318/https://www.telegraph.co.uk/obituaries/2021/09/16/sir-clive-sinclair-inventor-early-pocket-calculator-transformed/ |archive-date=18 November 2022 |location=London |date=16 September 2021}}</ref> Sinclair himself remarked that the keyboard's rubber mould was "unusual", but consumers were undeterred.<ref name=syntax/>

[[File:Harold Macmillan and Clive Sinclair.png|thumb|left|90 year-old [[Harold Macmillan]] using the ZX Spectrum with Sinclair looking on (1984)]]

Despite very high demand, Sinclair Research was "notoriously late" in delivering the ZX Spectrum. Their practice of offering mail-order sales before units were ready ensured a constant cash flow, but meant a lacking distribution.{{sfn|Leigh|2018|p=68}} [[Nigel Searle]], the newly-appointed chief of Sinclair's computer division, said in June 1982 the company had no plans to stock the new machine in [[WHSmith]], which was at the time Sinclair's only retailer.{{sfn|Clark|1982|p=43}} Searle explained that the mail-order system was in place due to there being no "obvious" retail outlets in the United Kingdom which could sell personal computers, and it made "better sense" financially to continue selling through mail-order.{{sfn|Clark|1982|p=44}} The company's conservative approach to distributing the machine was criticised,{{sfn|Leigh|2018|p=68}} with disillusioned customers telephoning and writing letters.{{sfn|Johnston|1982|p=4}}{{sfn|Pratt|1982a|p=4}} Demand sky-rocketed beyond Sinclair's planned 20,000 monthly unit output to a backlog of 30,000 orders by July 1982. Due to a scheduled holiday at the Timex factory that summer, the backlog had risen to 40,000 units. Sinclair issued a public apology in September that year,<ref name=registerhistory/> and promised that the backlog would be cleared by the end of that month.{{sfn|Johnston|1982|p=4}} Supply did not return to normal until the 1982 Christmas season, however.{{sfn|Leigh|2018|p=70}}

Production of the machine rapidly increased with the arrival of the less expensive Issue 2 [[motherboard]], a redesign of the main circuit board which addressed hardware manufacturing defects that affected production of the first model.{{sfn|Adamson|Kennedy|1986|p=256}} Sales of the ZX Spectrum reached 200,000 in its first nine months,{{sfn|Popular Computing Weekly|1983a|p=1}} rising to 300,000 for the whole of the first year.{{sfn|Backhurst|1983b|p=14}} By August 1983 total sales in Britain and Europe had exceeded 500,000,{{sfn|Popular Computing Weekly|1983c|p=1}} with the millionth Spectrum manufactured on 9 December 1983. By this point, an average of 50,000 units were being purchased each month.{{sfn|Popular Computing Weekly|1983d|p=5}}

In July 1983, an enhanced version of the ZX Spectrum was launched in the United States as the [[Timex Sinclair 2068]]. Advertisements described it as offering 72 kilobytes of memory, having a full range of colour and sound for a price under $200.<ref name="byte198312">{{cite news | url=https://archive.org/stream/byte-magazine-1983-12/1983_12_BYTE_08-12_Easy_Software#page/n281/mode/2up | title=Now from Timex...a powerful new computer. | work=BYTE | date=December 1983 | accessdate=20 October 2013 | author=Advertisement | pages=281}}</ref> Despite the improvements upon its British counterpart, sales proved poor and [[Timex Sinclair]] collapsed the following year.<ref name=registerhistory/>{{sfn|Bradbeer|1983|p=83}}<ref>{{cite web |title=Timex Sinclair 2068 - RTO - Computer - Computing History |url=https://www.computinghistory.org.uk/det/62128/Timex-Sinclair-2068-RTO/ |publisher=The Centre for Computing History |access-date=23 April 2024 |archive-url=https://web.archive.org/web/20240423204916/https://www.computinghistory.org.uk/det/62128/Timex-Sinclair-2068-RTO/ |archive-date=23 April 2024 |url-status=live}}</ref>

=== Success and market domination ===
[[File:Micro-computer wordt uitgeleend bij biobliotheek, bij wizej van experiment, Bestanddeelnr 933-0448 (colour).jpg|thumb|right|A woman is loaned a ZX Spectrum from a library in the Netherlands, 1984.]]
A crucial part of the company's marketing strategy was to implement regular price-cutting at strategic intervals to maintain [[market share]]. Ian Adamson and Richard Kennedy noted that Sinclair's method was driven by securing his leading position through "panicking" the competition. While most companies at the time reduced prices of their products while their market share was dwindling, Sinclair Research discounted theirs shortly after sales had peaked, throwing the competition into "utter disarray".{{sfn|Adamson|Kennedy|1986|p=143}} Sinclair Research made a profit of £14 million in 1983, compared to £8.5 million the previous year. [[Asset turnover|Turnover]] doubled from £27.2 million to £54.5 million, which equated to roughly £1 million for each person employed directly by the company.{{sfn|Segre|1983|p=18}}

Clive Sinclair became a focal point during the ZX Spectrum's marketing campaign by putting a human face onto the business. Sinclair Research was portrayed in the media as a "plucky" British challenger taking on the technical and marketing might of giant American and Japanese corporations. As David O'Reilly noted in 1986, "by astute use of public relations, particularly playing up his image of a Briton taking on the world, Sinclair has become the best-known name in micros."{{sfn|Adamson|Kennedy|1986|p=98}} The media latched onto Sinclair's image; his "Uncle Clive" persona is said to have been created by the gossip columnist for ''[[Personal Computer World]]''.{{sfn|Adamson|Kennedy|1986|p=97}} The press praised Sinclair as a visionary genius, with ''[[The Sun (United Kingdom)|The Sun]]'' lauding him as "the most prodigious inventor since [[Leonardo da Vinci]]". Adamson and Kennedy wrote that Sinclair outgrew the role of microcomputer manufacturer and "accepted the mantle of pioneering [[boffin]] leading Britain into a technological utopia".{{sfn|Adamson|Kennedy|1986|p=114}} Sinclair's contribution to the technology sector resulted in him being [[Knight Bachelor|knighted]] upon the recommendation of [[Margaret Thatcher]] in the [[1983 Birthday Honours|Queen's 1983 Birthday Honours List]].<ref name="bbctwo">{{cite web |title=Sir Clive Sinclair: Tireless inventor ahead of his time |url=https://www.bbc.co.uk/news/science-environment-29985976 |website=[[BBC News]] |access-date=18 October 2023 |archive-url=https://web.archive.org/web/20230518164253/https://www.bbc.co.uk/news/science-environment-29985976 |archive-date=18 May 2023 |location=London |date=16 September 2021}}</ref><ref name=mensabio>{{cite web |url=http://www.mensa.org.uk/cgi-bin/item.cgi?ap=1&id=279 |title=Biography of Sir Clive Sinclair |access-date=25 September 2007 |last=Goodenough |first=Jan |date=March 2000 |publisher=[[Mensa International|British Mensa]] |url-status=dead |archive-url=https://web.archive.org/web/20080202182911/http://www.mensa.org.uk/cgi-bin/item.cgi?ap=1&id=279 |archive-date=2 February 2008}}</ref><ref>{{cite web |last1=Bates |first1=Stephen |title=Sir Clive Sinclair obituary |url=https://www.theguardian.com/technology/2021/sep/17/sir-clive-sinclair |work=[[The Guardian]] |access-date=3 October 2023 |archive-url=https://web.archive.org/web/20230326032914/https://www.theguardian.com/technology/2021/sep/17/sir-clive-sinclair |archive-date=26 March 2023 |location=London |date=17 September 2021}}</ref>

The United Kingdom was largely immunised from the effects of the [[video game crash of 1983]], due to the saturation of home computers such as the ZX Spectrum.{{sfn|Leigh|2018|p=104}}<ref>{{cite web | url = https://www.ign.com/articles/2011/09/21/ten-facts-about-the-great-video-game-crash-of-83 | title = Ten Facts about the Great Video Game Crash of '83 | first = Nadia | last = Oxford | date = 18 January 2012 | access-date = 11 September 2020 | work = [[IGN]] | archive-date = 28 January 2021 | archive-url = https://web.archive.org/web/20210128072326/https://www.ign.com/articles/2011/09/21/ten-facts-about-the-great-video-game-crash-of-83 | url-status = live }}</ref><ref name="nerd">{{cite web |last1=Leigh |first1=Peter |title=ZX Spectrum Story: Celebrating 35 Years of the Speccy |url=https://www.nostalgianerd.com/zx-spectrum-story/ |publisher=Nostalgia Nerd |access-date=23 October 2023 |archive-url=https://web.archive.org/web/20230804184058/https://www.nostalgianerd.com/zx-spectrum-story/ |archive-date=4 August 2023 |date=21 April 2017}}</ref> The microcomputer market continued to grow and game development was unhindered despite the turbulence in the American markets. Indeed, computer games remained the dominant sector of the British home video game market up until they were surpassed by [[Sega]] and [[Nintendo]] consoles in 1991.{{sfn|His Majesty's Stationery Office|1995|pp=[https://i.imgur.com/CLYiKIp.jpg 66], [https://i.imgur.com/vR9vtPX.jpg 68]}} By the end of 1983 there were more than 450 companies in Britain selling video games on cassette, compared to 95 the year before.<ref name="wired uk history">{{cite magazine | url = https://www.wired.com/2010/06/sinclair-zx80/ | title = Sinclair ZX80 and the Dawn of 'Surreal' U.K. Game Industry | first = Chris | last = Baker | date = 6 August 2010 | access-date = 30 September 2019 | magazine = [[Wired (magazine)|Wired]] | archive-date = 26 July 2019 | archive-url = https://web.archive.org/web/20190726200228/https://www.wired.com/2010/06/sinclair-zx80/ | url-status = live }}</ref> An estimated 10,000 to 50,000 people, mostly young men, were developing games out of their homes based on advertisements in popular magazines. The growth of video games during this period has been compared to the [[punk subculture]], fuelled by young people making money from their games.<ref name="independent origins">{{cite web | url = https://www.independent.co.uk/life-style/gadgets-and-tech/features/geeks-who-rocked-the-world-documentary-looks-back-at-origins-of-the-computer-games-industry-9997037.html | title = Geeks Who Rocked The World: Documentary Looks Back At Origins Of The Computer-games Industry | first = Rhordi | last = Mardsen | date = 25 January 2015 | access-date = 3 October 2019 | work = [[The Independent]] | archive-date = 9 November 2019 | archive-url = https://web.archive.org/web/20191109005014/https://www.independent.co.uk/life-style/gadgets-and-tech/features/geeks-who-rocked-the-world-documentary-looks-back-at-origins-of-the-computer-games-industry-9997037.html | url-status = live }}</ref>

By the mid 1980s, Sinclair Research's share of the British home computer market had climbed to a high of 40 per cent.<ref name=newyorkdeal/> Sales in the 1984 Christmas season were described as "extremely good".{{sfn|Bourne|1985a|p=7}} In early 1985 the British press reported the home computer boom to have ended,<ref>{{cite web |title=The 80s home computer boom (video) |url=https://www.bbc.co.uk/programmes/p0336d72 |website=[[BBC Radio 4]] |publisher=[[BBC]] |access-date=24 October 2023 |archive-url=https://web.archive.org/web/20150926051715/https://www.bbc.co.uk/programmes/p0336d72 |archive-date=26 September 2015 |location=London |date=22 September 2015 |url-status=live}}</ref> leaving many companies slashing prices of their hardware to anticipate lower sales.{{sfn|Bourne|1985a|p=7}} Despite this, celebration of Sinclair's success in the computing market continued at the ''[[Which?|Which Computer?]]'' show in [[Birmingham]], where the five-millionth Sinclair machine (a gold coloured QL) was issued as a prize.{{sfn|Bourne|1985a|p=7}}

=== Later years and company decline ===
[[File:Sinclair sale to Amstrad 1986 Sinclair Sugar handshake.jpg|thumb|Sinclair shaking hands with [[Alan Sugar]], to mark the conclusion of the sale to [[Amstrad]] in 1986]]
The ZX Spectrum's successor, the [[Sinclair QL]], was officially announced on 12 January 1984, shortly before the [[Macintosh 128K]] went on sale.{{sfn|Denham|1984a|p=4}} Contrasting with its predecessors, the QL was aimed at more serious, professional home users.{{sfn|Sawford|1984|p=47}} It suffered from several design flaws; fully operational QLs were not available until the late summer, and complaints against Sinclair concerning delays were upheld by the [[Advertising Standards Authority (United Kingdom)|Advertising Standards Authority]] (ASA) in May of that year. Particularly serious were allegations that Sinclair was cashing cheques months before machines were shipped. By autumn 1984, Sinclair was still publicly forecasting that it would be a "million seller" and that 250,000 units would be sold by the end of the year.{{sfn|Munford|1984|p=72}} QL production was suspended in February 1985, and the price was halved by the end of the year.<ref name="Timex/Sinclair history">{{cite web|url=http://www.zqaonline.com/Events/History.aspx|title=Timex/Sinclair history|work=ZQAOnline|access-date=15 December 2006|url-status=dead|archive-url=https://web.archive.org/web/20060717042421/http://www.zqaonline.com/Events/History.aspx|archive-date=17 July 2006}}</ref> It ultimately flopped, with 139,454 units being manufactured.<ref>{{cite web |last1=Smith |first1=Tony |title=Sinclair's 1984 big shot at business: The QL is 30 years old |url=https://www.theregister.com/2014/01/12/archaeologic_sinclair_ql/?page=2 |website=[[The Register]] |publisher=Situation Publishing |access-date=26 October 2023 |archive-url=https://web.archive.org/web/20221212112255/https://www.theregister.com/2014/01/12/archaeologic_sinclair_ql/?page=2 |archive-date=12 December 2022 |location=London |language=en}}</ref>

The ZX Spectrum+, a rebranded ZX Spectrum with identical technical specifications except for the QL-like keyboard, was introduced in October 1984 and made available in WHSmith's stores the day after its launch. Retailers stocked the device in high quantities, anticipating robust Christmas sales. Nevertheless, the product did not perform as well as projected, leading to a significant drop in Sinclair's income from orders in January, as retailers were left with surplus stock. Subsequently, an upgraded model, the ZX Spectrum 128, was released in Spain in September 1985, with development financed by the Spanish distributor Investrónica.<ref name="Kept in the Dark">{{cite magazine | date = November 1985 | title = Kept in the Dark | magazine = [[Crash (magazine)|CRASH]] | issue = 22 | url = http://www.crashonline.org.uk/22/editrl.htm | access-date = 15 December 2006 | archive-date = 14 May 2011 | archive-url = https://web.archive.org/web/20110514040006/http://www.crashonline.org.uk/22/editrl.htm | url-status = live }}</ref> The launch of this model in the UK was postponed until January 1986 due to the substantial leftover inventory of the prior model.<ref name="comphist-spec128">{{cite web|url=http://www.computinghistory.org.uk/cgi-bin/sitewise.pl?act=det&p=2584|title=Sinclair ZX Spectrum 128|publisher=The Centre for Computing History|access-date=4 December 2009|archive-date=21 August 2010|archive-url=https://web.archive.org/web/20100821130000/http://www.computinghistory.org.uk/cgi-bin/sitewise.pl?act=det&p=2584|url-status=live}}</ref>

While the Sinclair QL was in development, Sinclair also hoped to repeat his success with the Spectrum in the fledgling electric vehicle market, which he saw as ripe for a new approach. On 10 January 1985, Sinclair unveiled the [[Sinclair C5]], a small one-person [[battery electric vehicle|battery electric]] [[Recumbent bicycle|recumbent]] [[tricycle]]. It marked the culmination of Sir Clive's long-running interest in electric vehicles.{{sfn|Dale|1985|p=151}} The C5 turned out to be a significant commercial failure, selling only 17,000 units and losing Sinclair £7 million. It has since been described as "one of the great marketing bombs of postwar British industry".{{sfn|Fraser|1986|p=14}} The ASA ordered Sinclair to withdraw advertisements for the C5 after finding that the company's claims about its safety could not be proved or justified.<ref>{{cite news|title=C5 advert claims rejected|date=17 July 1985|work=[[The Times]]|publisher=[[News Corp]]|location=London|page=3}}</ref>

The combined failures of the C5 and QL caused investors to lose confidence in Sinclair's judgement. In May 1985, Sinclair Research announced their intention to raise an additional £10 to £15 million to restructure the organisation. Given the loss of confidence in the company, securing the funds proved to be a challenging task. In June 1985, business magnate [[Robert Maxwell]] disclosed a takeover bid for Sinclair Research through Hollis Brothers, a subsidiary of his [[Pergamon Press]].<ref name="nyt-srl">{{cite news|url=https://www.nytimes.com/1985/06/18/business/sinclair-to-sell-british-unit.html|title=Sinclair to Sell British Unit|date=18 June 1985|work=[[The New York Times]]|agency=[[Associated Press]]|url-access=limited|access-date=4 December 2009|archive-date=18 May 2013|archive-url=https://web.archive.org/web/20130518140601/http://www.nytimes.com/1985/06/18/business/sinclair-to-sell-british-unit.html|url-status=live}}</ref> However, the deal was terminated in August 1985.<ref name="newyorkdeal">{{cite news |title=Hollis pulls out of Sinclair offer |url=https://www.nytimes.com/1985/08/10/business/hollis-pulls-out-of-sinclair-offer.html |access-date=19 October 2023 |work=[[The New York Times]] |date=10 August 1985 |archive-url=https://web.archive.org/web/20230516175942/https://www.nytimes.com/1985/08/10/business/hollis-pulls-out-of-sinclair-offer.html |archive-date=16 May 2023 |location=New York City |page=32}}</ref> The future of Sinclair Research remained uncertain until 7 April 1986, when the company sold their entire computer product range, along with the "Sinclair" brand name, to [[Alan Sugar]]'s [[Amstrad]] for £5 million.{{sfn|Kidd|1986|p=7}} The takeover sent ripples through the [[London Stock Exchange]], but Amstrad's shares soon recovered, with one stock broker affirming that "[[City of London|the City]] appears to have taken the news in its stride".{{sfn|Scolding|1986|p=7}} Amstrad's acquisition of the brand name saw the release of three ZX Spectrum models throughout the late 1980s, each with varying improvements.{{sfn|Phillips|1986|p=47}}

By 1990, Sinclair Research consisted of Sinclair and two other employees down from 130 employees at its peak in 1985.<ref>{{cite web | url = https://www.nytimes.com/1985/05/19/magazine/inventing-the-future.html | title = Inventing the Future | first = Barnaby | last = Feder | date = 19 May 1985 | accessdate = 18 September 2021 | work = [[The New York Times]]|location=New York City|archiveurl=https://web.archive.org/web/20230516193313/https://www.nytimes.com/1985/05/19/magazine/inventing-the-future.html|archivedate=16 May 2023}}</ref> The ZX Spectrum was officially discontinued in 1992, after ten years on the market.{{sfn|Leigh|2018|p=70}}<ref name="bbclegacy" /> Sinclair Research continued to exist as a one-man company, marketing Sir Clive Sinclair's inventions until his death in September 2021.

== Hardware ==
=== Technical specifications ===
[[File:Zx-colors.png|thumb|right|The ZX Spectrum's full [[Palette (computing)|colour palette]] ]]
The [[central processing unit]] is a [[Zilog Z80]], an 8-bit [[microprocessor]], with a [[clock rate]] of 3.5&nbsp;[[Hertz#SI multiples|MHz]]. The original model Spectrum has 16&nbsp;KB of ROM and either 16&nbsp;KB or 48&nbsp;KB of RAM.{{sfn|Leigh|2018|p=70}}

=== Graphics ===
{{See also|ZX Spectrum graphic modes}}
Video output is channelled through an [[RF modulator]], intended for use with contemporary television sets, to provide a simple colour graphic display. Text is displayed using a grid of 32&nbsp;columns × 24&nbsp;rows of characters from the [[ZX Spectrum character set]], or from a custom set. The machine features a colour palette of 15 colours, consisting of seven saturated colours at two levels of brightness, along with black.<ref name="Vickers">{{Cite book |last= Vickers |first= Steven |title= Sinclair ZX Spectrum BASIC Programming |url= http://www.worldofspectrum.org/ZXBasicManual/ |access-date= 23 August 2006 |year= 1982 |publisher= [[Sinclair Research Ltd]] |chapter= Introduction |chapter-url= http://www.worldofspectrum.org/ZXBasicManual/zxmanchap1.html |url-status= live |archive-url= https://web.archive.org/web/20060924115058/http://www.worldofspectrum.org/ZXBasicManual/ |archive-date= 24 September 2006 }}</ref> The [[image resolution]] is 256×192 pixels, subject to the same colour limitations.<ref name="SpectrumManualChapter16">{{Cite book |last= Vickers |first= Steven |title= Sinclair ZX Spectrum BASIC Programming |url= http://www.worldofspectrum.org/ZXBasicManual/ |access-date= 23 August 2006 |year= 1982 |publisher= [[Sinclair Research Ltd]] |chapter= Colours |chapter-url= http://www.worldofspectrum.org/ZXBasicManual/zxmanchap16.html |url-status= live |archive-url= https://web.archive.org/web/20060924115058/http://www.worldofspectrum.org/ZXBasicManual/ |archive-date= 24 September 2006 }}</ref> To optimise memory usage, colour is stored separately from the pixel [[bitmap]] in a low resolution, 32×24 grid overlay, corresponding to the character cells. In practical terms, this means that all pixels within an 8x8 character block share one foreground colour and one background colour. Altwasser received a patent for this design.<ref name="Altwasser">{{Cite patent |country=EP |number=0107687 |status = patent |title=Display for a computer |gdate=6 July 1988 |fdate=22 April 1983 |pridate=22 April 1982 |invent1=Richard Francis Altwasser |assign1=Sinclair Research Ltd }}</ref>

An "attribute" consists of a foreground and a background colour, a brightness level (normal or bright) and a flashing "flag" which, when set, causes the two colours to swap at regular intervals.<ref name="SpectrumManualChapter16" /> This scheme leads to what was dubbed "colour clash" or [[attribute clash]], where a desired colour of a specific pixel could not be selected, but only the colour attributes of an 8x8 block. This became a distinctive feature of the Spectrum, requiring programs, especially games, to be designed with this limitation in mind. In contrast, other machines available at the same time, such as the [[Amstrad CPC]] or the [[Commodore 64]], did not suffer from this limitation. While the Commodore 64 also employed colour attributes, it utilised a special multicolour mode and hardware [[sprite (computer graphics)|sprites]] to circumvent attribute clash.<ref name="digitalfoundry">{{cite web|url=http://www.eurogamer.net/articles/digitalfoundry-face-off-zx-spectrum-vs-commodore-64|title=Face off – ZX Spectrum vs Commodore 64|website=[[Eurogamer]]|publisher=[[Future plc]]|location=[[Bath, Somerset|Bath]]|date=29 April 2012|access-date=28 August 2012|url-status=live|archive-url=https://web.archive.org/web/20120904041518/http://www.eurogamer.net/articles/digitalfoundry-face-off-zx-spectrum-vs-commodore-64|archive-date=4 September 2012}}</ref>

[[File:MSX Computer Color Limit.gif|thumb|left|The effect of [[attribute clash]] on an [[MSX]], similar to a ZX Spectrum]]

=== Sound ===
Sound output is produced through a built-in beeper capable of generating a single channel with ten octaves.{{sfn|Wilkins|2015b|p=16}} It is controlled by a single {{code|EAR}} bit.<ref name="worldofspectrum-16-48">{{Cite book |title= 16K / 48K ZX Spectrum Reference |chapter-url= https://worldofspectrum.org/faq/reference/48kreference.htm#PortFE |publisher=  |chapter= PortFE |access-date= 4 July 2023 |archive-date= 25 March 2023 |archive-url= https://web.archive.org/web/20230325133729/https://worldofspectrum.org/faq/reference/48kreference.htm#PortFE |url-status= live }}</ref> By toggling it on and off, simple sounds are generated. This speaker, capable of producing just one note at a time, was governed by the [[BASIC]] command 'BEEP', where programmers could manipulate parameters for pitch and duration.{{sfn|Wilkins|2015a|p=16}} Furthermore, the processor remained occupied exclusively with the BASIC BEEPs until their completion, limiting concurrent operations. Despite these constraints, it marked a significant step forward from the [[ZX81]], which lacked any sound capabilities. Resourceful programmers swiftly devised workarounds; its rudimentary audio functionality compelled developers to explore unconventional methods such as programming the beeper to emit multiple pitches.{{sfn|Wilkins|2015a|p=17}}

Later software became available that allowed for two-channel sound playback. The machine includes an [[expansion bus]] [[edge connector]] and 3.5&nbsp;mm audio in/out ports, facilitating the connection of a [[cassette recorder]] for loading and saving programs and data. The {{code|EAR}} port has a higher output than the {{code|MIC}} and is recommended for headphones, while the {{code|MIC}} port is intended for attachment to other audio devices as a [[line level|line-in]] source.<ref name="Vickers-19">{{Cite book |last= Vickers |first= Steven |title= Sinclair ZX Spectrum BASIC Programming |chapter-url= http://www.worldofspectrum.org/ZXBasicManual/zxmanchap19.html |publisher= [[Sinclair Research Ltd]] |chapter= BEEP |url-status= live |archive-url= https://web.archive.org/web/20141113055815/http://www.worldofspectrum.org/ZXBasicManual/zxmanchap19.html |archive-date= 13 November 2014 }}</ref>

=== Other integrated peripherals ===
The ZX Spectrum integrated elements from the ZX81. The keyboard decoding and cassette interfaces are nearly identical, although the latter was programmed for higher-speed loading and saving. The central ULA [[integrated circuit]] shares some resemblance with that of the ZX81, but it features a hardware-based television raster generator with colour support. This indirectly provides the new machine with roughly four times the processing power of the ZX81, as the Z80 is relieved of video generation tasks. An initial ULA design flaw occasionally led to incorrect keyboard scanning, which was resolved by adding a small [[Printed circuit board|circuit board]] mounted upside down next to the CPU in Issue 1 ZX Spectrums.{{sfn|Kean|1985b|p=127}}

=== Firmware ===
[[File:ZXspectrum mb.jpg|thumb|48K motherboard (Issue 3B: 1983, heat sink removed)]]
The machine's [[Sinclair BASIC]] interpreter is stored in 16&nbsp;KiB ROM, along with essential system routines. The ROM code, responsible for tasks such as [[floating point]] calculations and [[parser|expression parsing]], exhibited significant similarities to ZX81, although a few outdated routines remained in the Spectrum ROM.{{sfn|Nash|1984|p=217}} The Spectrum's keyboard is imprinted with BASIC keywords. To input a command in BASIC, many keywords require a single keyboard stroke. Other keywords require a change of keyboard mode by a few keystrokes.<ref name="Vickers-2">{{Cite book |last= Vickers |first= Steven |title= Sinclair ZX Spectrum BASIC Programming |url= http://www.worldofspectrum.org/ZXBasicManual/ |access-date= 19 September 2006 |year= 1982 |publisher= [[Sinclair Research Ltd]] |chapter= Basic programming concepts |chapter-url= http://www.worldofspectrum.org/ZXBasicManual/zxmanchap2.html |url-status= live |archive-url= https://web.archive.org/web/20060924115058/http://www.worldofspectrum.org/ZXBasicManual/ |archive-date= 24 September 2006 }}</ref>

The BASIC interpreter is derived from the one used on the [[ZX81]]. A BASIC program for ZX81 can be entered into a ZX Spectrum with minimal modifications. However, Spectrum BASIC introduced numerous additional features, enhancing its usability. The [[ZX Spectrum character set]] was expanded compared to that of the ZX81, which lacked lowercase letters. Spectrum BASIC incorporated extra keywords for better graphics and sound functionality, and support for multi-statement lines was added. The built-in ROM tape modulation software routines for cassette data storage enable data transfers at an average speed of 171 [[bit rate|bits per second]] (bit/s), with a theoretical peak speed of 256 bit/s. The tape modulation is significantly more advanced than the ZX81, with approximately four times faster average speeds.<ref name="myprius">{{cite web|url=http://www.myprius.co.za/tape_storage.htm|title=Tape Data Storage|access-date=19 August 2012|url-status=live|archive-url=https://web.archive.org/web/20120415055937/http://www.myprius.co.za/tape_storage.htm|archive-date=15 April 2012}}</ref>

== Sinclair Research models ==

=== ZX Spectrum 16K/48K ===
[[file:ZXSpectrum48k.jpg|thumb|ZX Spectrum 16K/48K (Dimensions (mm): 233×144×30 (W×H×D) @ ≈552 grams).<ref name = HCHOF>{{cite web | url = http://www.gondolin.org.uk/hchof/hchof.php | title = The Home Computers Hall of Fame, The Machines | last = Stratford | first = Christopher | date = 11 May 2014 | website = gondolin.org.uk | archive-url = https://web.archive.org/web/20150317112736/http://gondolin.org.uk/hchof/hchof.php | archive-date = 17 March 2015 | url-status = live | access-date = 31 March 2015 }}</ref>]]

The original ZX Spectrum is remembered for its rubber [[chiclet keyboard]], diminutive size and distinctive rainbow motif. It was originally released on 23 April 1982 with 16&nbsp;KB of RAM for {{inflation|UK|125|1982|fmt=eq|cursign=£|orig=yes}} or with 48&nbsp;KB for {{inflation|UK|175|1982|fmt=eq|cursign=£|orig=yes}};<ref name="High Street Spectrum">{{Cite journal |date= February 1983 |title= The High Street Spectrum |journal= ZX Computing |page= [https://archive.org/details/ZX-computing-1983-02/page/n42 43] |url= https://archive.org/details/ZX-computing-1983-02 |access-date= 27 April 2016 |url-status= live |archive-url= https://web.archive.org/web/20170316134253/https://archive.org/details/ZX-computing-1983-02 |archive-date= 16 March 2017 }}<!-- This cannot be fixed via Wayback archive due to robots.txt preventing archiving of the site. --></ref> these prices were reduced to {{inflation|UK|99|1983|fmt=eq|cursign=£|orig=yes}} and {{inflation|UK|129|1983|fmt=eq|cursign=£|orig=yes}} respectively in 1983.{{sfn|Gilbert|1983a|p=13}} Owners of the 16&nbsp;KB model could purchase an internal 32&nbsp;KB RAM upgrade, which for early "Issue 1" machines consisted of a [[daughterboard]]. Later issue machines required the fitting of 8 [[dynamic random-access memory|dynamic RAM]] chips and a few [[transistor-transistor logic|TTL]] chips. Users could mail their 16K Spectrums to Sinclair to be upgraded to 48&nbsp;KB versions. Later revisions contained 64&nbsp;KB of memory but were configured such that only 48&nbsp;KB were usable.<ref name = ys-64k-1984-09>{{Cite journal | last = Goodwin | first = Simon | date = September 1984 | title = Suddenly, it's the 64K Spectrum! | journal = [[Your Spectrum]] | issue = 7 | pages = 33–34 | url = http://www.users.globalnet.co.uk/~jg27paw4/yr07/yr07_33.htm | archive-url = https://web.archive.org/web/20140522194918/http://www.users.globalnet.co.uk/~jg27paw4/yr07/yr07_33.htm | archive-date = 22 May 2014 | url-status = live | access-date = 31 March 2015 | quote = So the first three issues of the Spectrum used a combination of eight 16K chips and eight 32K ones. The latest machines depart from that combination, but Sinclair Research has been very quiet about the alteration. }}</ref> External 32&nbsp;KB RAM packs that mounted in the rear expansion slot were available from third parties. Both machines had 16&nbsp;KB of onboard ROM.{{sfn|Leigh|2018|p=68}}

An "Issue 1" ZX Spectrum can be distinguished from Issue 2 or 3 models by the colour of the keys – light grey for Issue 1, blue-grey for later machines.<ref name = ps-s48kv-2003-09>{{cite web | url = http://www.nvg.ntnu.no/sinclair/computers/zxspectrum/spec48versions.htm | work = Planet Sinclair | title = Spectrum 48K Versions | last = Owen | first = Chris | archive-url = https://web.archive.org/web/20150321023603/http://rk.nvg.ntnu.no/sinclair/computers/zxspectrum/spec48versions.htm | date = 6 September 2003 | archive-date = 21 March 2015 | url-status = live | access-date = 31 March 2015 | quote = It is often possible to determine which version of the Spectrum 16/48K one has without opening the case, as there are a number of clues... }}</ref> Although the official service manual states that approximately 26,000 of these original boards were manufactured,<ref name="Servicing">{{cite book |last1=Thorn (EMI) Datatech Ltd|title=Servicing Manual For ZX Spectrum |date=March 1984 |publisher=Sinclair Research Ltd |page=4.3 |url=https://k1.spdns.de/Vintage/Sinclair/82/Sinclair%20ZX%20Spectrum/Repair/ZX%20Spectrum%20Service%20Manual%20(OCRed).pdf |access-date=31 January 2019 |archive-url=https://web.archive.org/web/20190201013410/https://k1.spdns.de/Vintage/Sinclair/82/Sinclair%20ZX%20Spectrum/Repair/ZX%20Spectrum%20Service%20Manual%20%28OCRed%29.pdf |archive-date=1 February 2019 |url-status=live }}</ref> subsequent serial number analysis shows that only 16,000 were produced, almost all of which fell in the serial number range 001-000001 to 001-016000.<ref>{{Cite web|title=ZX Spectrum Models|url=https://spectrumforeveryone.com/technical/zx-spectrum-models/|access-date=9 September 2021|website=Spectrum for Everyone|language=en-GB|archive-date=9 September 2021|archive-url=https://web.archive.org/web/20210909125915/https://spectrumforeveryone.com/technical/zx-spectrum-models/|url-status=live}}</ref> An online tool now exists to allow users to ascertain the likely issue number of their ZX Spectrum by inputting the serial number.<ref>{{Cite web|title=Spectrum For Everyone Serial DB|url=https://serials.spectrumforeveryone.com/|access-date=9 September 2021|website=Spectrum For Everyone Serial DB|language=en|archive-date=9 September 2021|archive-url=https://web.archive.org/web/20210909125915/https://serials.spectrumforeveryone.com/|url-status=live}}</ref>

These models experienced numerous changes to its motherboard design throughout its life; mainly to improve manufacturing efficiencies, but also to correct bugs from previous boards. Another issue was with the Spectrum's power supply. In March 1983, Sinclair issued an urgent recall warning for all owners of models bought after 1 January 1983.{{sfn|Popular Computing Weekly|1983b|p=6}} Plugs with a non-textured surface were at risk of causing shock, and were asked to be sent back to a warehouse in [[Cambridgeshire]] which would supply a replacement within 48 hours.{{sfn|Popular Computing Weekly|1983b|p=6}}{{sfn|Backhurst|1983a|p=5}}

=== ZX Spectrum+ {{anchor|plus}}===
[[file:ZX Spectrum+.jpg|thumb|ZX Spectrum+ (Dimensions (mm): 319×149×38 (W×H×D))<ref name=HCHOF />]]

Development of the ''ZX Spectrum+'' began in June 1984,{{sfn|Denham|1984b|p=104}} and was released on 15 October that year at £179.<ref name="New Spectrum">{{Cite journal |date= December 1984 |title= News: New Spectrum launch |journal= [[Sinclair User]] |issue= 33 |page= 11 |url= http://www.sincuser.f9.co.uk/033/news.htm |access-date= 19 August 2006 |url-status= dead |archive-url= https://web.archive.org/web/20060924094040/http://www.sincuser.f9.co.uk/033/news.htm |archive-date= 24 September 2006 }}</ref><ref name='hcw231084'>{{cite magazine|title=Spectrum surprise!|magazine=Home Computing Weekly|issue=85|publisher=Argus Specialist Publications|date=23 October 1984|page=1|url=https://spectrumcomputing.co.uk/page.php?issue_id=2651&page=1|access-date=23 May 2021|archive-date=24 September 2020|archive-url=https://web.archive.org/web/20200924170531/https://spectrumcomputing.co.uk/page.php?issue_id=2651&page=1|url-status=dead}}</ref><ref name="PSZX+">{{cite web |url=http://www.nvg.ntnu.no/sinclair/computers/zxspectrum/specplus.htm |work=Planet Sinclair |last=Owen |first=Chris |access-date=21 August 2006 |title=ZX Spectrum+ |url-status=live |archive-url=https://web.archive.org/web/20110903053833/http://www.nvg.ntnu.no/sinclair/computers/zxspectrum/specplus.htm |archive-date=3 September 2011 }}</ref> It was assembled by AB Electronics in [[South Wales]] and [[Samsung]] in South Korea.<ref name="Goodwin-145" /> This 48 KB Spectrum introduced a new [[Sinclair QL|QL]]-style case with an injection-moulded keyboard and a reset button that functions as a switch shorting across the CPU reset capacitor. Electronically, it was identical to the previous 48&nbsp;KB model. The machine outsold the rubber-key model two to one,{{sfn|Denham|1984b|p=104}} however, some retailers reported a failure rate of up to 30%, compared with a more typical 5–6% for the older model.<ref name="PSZX+" /> In early 1985, the original Spectrum was officially discontinued, and the ZX Spectrum+ was reduced in price to £129.{{sfn|Bourne|1985a|p=7}}

=== ZX Spectrum 128 {{anchor|spectrum128}}===
[[file:ZX Spectrum128K.jpg|thumb|ZX Spectrum 128]]

In 1985, Sinclair developed the ZX Spectrum 128 (codenamed ''Derby'') in conjunction with their Spanish distributor Investrónica (a subsidiary of [[El Corte Inglés]] department store group).{{sfn|Frey|1985|p=5}}{{sfn|Bourne|1985b|p=5}}{{sfn|Frey|1986|p=11}} Investrónica had helped adapt the ZX Spectrum+ to the Spanish market after their government introduced a special tax on all computers with 64&nbsp;KB RAM or less,<ref>{{in lang|es}} Ministerio de Economía y Hacienda (BOE 211 de 3 September 1985), [http://www.boe.es/buscar/doc.php?id=BOE-A-1985-18847 Real Decreto 1558/1985, de 28 de agosto, por el que se aclara el alcance del mínimo específico introducido en la subpartida 84.53.B.II del Arancel de Aduanas, por el Real Decreto 1215/1985] {{webarchive|url=https://web.archive.org/web/20130430111506/http://www.boe.es/buscar/doc.php?id=BOE-A-1985-18847 |date=30 April 2013 }}. Rango: Real Decreto, Páginas: 27743 – 27744, Referencia: 1985/18847.</ref> and a law which obliged all computers sold in Spain to support the Spanish alphabet and show messages in Spanish.<ref name="BOE">{{in lang|es}} Ministerio de Industria y Energía (BOE 179 de 27 July 1985), [http://www.boe.es/buscar/doc.php?id=BOE-A-1985-15611 Real Decreto 1250/1985, de 19 de junio, por el que se establece la sujeción a especificaciones técnicas de los terminales de pantalla con teclado, periféricos para entrada y representación de información en equipo de proceso de datos] {{webarchive|url=https://web.archive.org/web/20130430104621/http://www.boe.es/buscar/doc.php?id=BOE-A-1985-15611 |date=30 April 2013 }}. Rango: Real Decreto, <!--pages, or pp. here? --> Páginas: 23840–23841, Referencia: 1985/15611.</ref>

The appearance of the ZX Spectrum 128 is similar to the ZX Spectrum+, with the addition of a large external [[heat sink|heatsink]] for the internal 7805 [[voltage regulator]] to the right-hand end of the case, replacing the internal heatsink in previous versions. This external [[Heat sink|heatsink]] led to the system's nickname, "The [[Toast rack|Toast Rack]]".<ref>{{cite web|url=http://retrorevivalshop.co.uk/index.php?main_page=product_info&cPath=7&products_id=60|title=Murata 5v Switching Regulator (for Toastrack models)|website=Retro Revival Shop|access-date=13 November 2021|archive-date=13 November 2021|archive-url=https://web.archive.org/web/20211113115246/http://retrorevivalshop.co.uk/index.php?main_page=product_info&cPath=7&products_id=60|url-status=live}}</ref> New features included 128&nbsp;KB RAM with RAM disc commands, three-channel audio via the [[General Instrument AY-3-8910|AY-3-8912]] chip, [[MIDI]] compatibility, an [[RS-232]] serial port, an [[RGB]] monitor port, 32&nbsp;KB of ROM including an improved BASIC editor, and an external keypad.{{sfn|Wilkins|2015a|p=17}}

The machine was simultaneously unveiled for the first time and launched in September 1985 at the [[SIMO TCI|SIMO '85]] trade show in Spain, with a price of 44,250 [[Spanish peseta|pesetas]]. Sinclair later presented the ZX Spectrum 128 at [[The May Fair Hotel]]'s Crystal Rooms in London, where he acknowledged that entertainment was the most common use of home computers. Due to the large number of unsold Spectrum+ models, Sinclair decided not to start it selling in the United Kingdom until January 1986 at a price of £179.<ref name="sincuser-49">{{Cite journal|date=April 1985 |title=<!-- wrong title this is quote: -->Clive discovers games – at last |journal=[[Sinclair User]] |issue=49 |page=53 |url=http://www.sincuser.f9.co.uk/049/128lnch.htm |url-status=dead |archive-url=https://web.archive.org/web/20060924093908/http://www.sincuser.f9.co.uk/049/128lnch.htm |archive-date=24 September 2006 }}</ref><ref name=nerd/>

The [[Zilog Z80]] processor used in the Spectrum has a [[16-bit computing|16-bit]] address bus, which means only 64&nbsp;KB of memory can be directly addressed. To facilitate the extra 80&nbsp;KB of RAM the designers used [[bank switching]] so the new memory would be available as eight pages of 16&nbsp;KB at the top of the address space. The same technique was used to page between the new 16&nbsp;KB editor ROM and the original 16&nbsp;KB BASIC ROM at the bottom of the address space.<ref name="128+3-Manual-8">{{cite web|url=http://www.worldofspectrum.org/ZXSpectrum128+3Manual/chapter8pt24.html|title=Spectrum 128+3 Manual, Chapter 8 Part 24|publisher=Amstrad|access-date=20 August 2012|url-status=live|archive-url=https://web.archive.org/web/20120615075843/http://www.worldofspectrum.org/ZXSpectrum128+3Manual/chapter8pt24.html|archive-date=15 June 2012}}</ref>

The new sound chip and [[MIDI]] out abilities were exposed to the BASIC programming language with the command <code>PLAY</code> and a new command <code>SPECTRUM</code> was added to switch the machine into 48K mode, keeping the current BASIC program intact (although there is no command to switch back to 128K mode). To enable BASIC programmers to access the additional memory, a RAM disk was created where files could be stored in the additional 80&nbsp;KB of RAM. The new commands took the place of two existing user-defined-character spaces causing compatibility problems with certain BASIC programs.<ref name="128+3-Manual-7">{{cite web|url=http://www.worldofspectrum.org/ZXSpectrum128+3Manual/chapter7.html|title=Spectrum 128+3 Manual, Chapter 7|publisher=Amstrad|access-date=20 August 2012|url-status=live|archive-url=https://web.archive.org/web/20120615074428/http://www.worldofspectrum.org/ZXSpectrum128+3Manual/chapter7.html|archive-date=15 June 2012}}</ref> Unlike its predecessors, it has no internal speaker, and can only produce sound from a television speaker.<ref name="128-Manual-9">{{cite web|url=http://www.worldofspectrum.org/ZXSpectrum128Manual/sp128p09.html|title=World of Spectrum – Documentation – ZX Spectrum 128 Manual Page 9|access-date=28 April 2016|url-status=live|archive-url=https://web.archive.org/web/20160424174241/http://www.worldofspectrum.org/ZXSpectrum128Manual/sp128p09.html|archive-date=24 April 2016}}</ref>

== Amstrad models ==

=== ZX Spectrum +2 {{anchor|plus2}}===
[[file:ZX Spectrum Plus2 (retouched).jpg|thumb|ZX Spectrum +2]]

The ''ZX Spectrum +2'' marked Amstrad's entry into the Spectrum market shortly after their [[Sinclair Research Ltd#Amstrad acquisition|acquisition of the Spectrum range and "Sinclair" brand]] in 1986. This machine featured a brand-new grey case with a spring-loaded keyboard, dual joystick ports, and an integrated cassette recorder known as the "Datacorder," akin to the [[Amstrad CPC 464]]. The ROM was updated so that the screen on boot-up showed an Amstrad copyright message (''© 1986 Amstrad'' in place of the previous ''© 1982 Sinclair Research Ltd''). However, it was largely identical to the ZX Spectrum 128 in most technical aspects. The machine retailed for £149.{{sfn|Phillips|1986|p=47}}

The new keyboard did not feature the BASIC keyword markings seen on earlier Spectrums, except for the keywords <code>LOAD</code>'','' <code>CODE</code>'','' and <code>RUN</code>'','' which were useful for loading software. Instead, the +2 introduced a menu system, almost identical to that of the ZX Spectrum 128, allowing users to switch between 48K BASIC programming with keywords and 128K BASIC programming, where all words, both keywords and others, needed to be typed out in full (though keywords were still stored internally as one character each). Despite these changes, the layout remained identical to that of the 128.<ref name="Goodwin-145" />

=== ZX Spectrum +3 {{anchor|plus3}}===
[[file:ZX Spectrum Plus3.jpeg|thumb|ZX Spectrum +3]]
The ''ZX Spectrum +3'', which was launched in 1987, bore a resemblance to its predecessor but introduced a built-in 3-inch [[floppy disk]] drive instead of the cassette drive. Initially priced at £249,<ref name="South">{{Cite journal |last= South |first= Phil |date= July 1987 |title= It's here... the Spectrum +3 |journal= [[Your Sinclair]] |issue= 17 |pages= 22–23 |url= http://www.worldofspectrum.org/showmag.cgi?mag=YourSinclair/Issue19/Pages/YourSinclair1900022.jpg |access-date= 5 August 2008 |archive-date= 9 August 2012 |archive-url= https://web.archive.org/web/20120809145932/http://www.worldofspectrum.org/showmag.cgi?mag=YourSinclair/Issue19/Pages/YourSinclair1900022.jpg |url-status= live }}</ref> it later retailed for £199.<ref name="sincuser-68">{{Cite journal |author= Amstrad |date= November 1987 |title= The new Sinclair has one big disk advantage |journal= [[Sinclair User]] |issue= 68 |pages= 2–3 |url= http://www.worldofspectrum.org/showmag.cgi?mag=SinclairUser/Issue068/Pages/SinclairUser06800002.jpg |access-date= 5 August 2008 |author-link= Amstrad |archive-date= 25 August 2012 |archive-url= https://web.archive.org/web/20120825201005/http://www.worldofspectrum.org/showmag.cgi?mag=SinclairUser/Issue068/Pages/SinclairUser06800002.jpg |url-status= live }}</ref> It was the only Spectrum model capable of running the [[CP/M]] operating system without additional hardware. Unlike its predecessors, the ZX Spectrum +3 power supply utilised a DIN connector and featured "Sinclair +3" branding on the case.<ref>{{cite web|url=http://www.yorkdistribution.co.uk/acatalog/Power-supply-for-Spectrum-128---2A---3-PS_SPE3.html|title=Power supply for Spectrum 128, +2A, +3|publisher=York Distribution Limited|access-date=21 December 2012|url-status=dead|archive-url=https://web.archive.org/web/20160829065203/http://www.yorkdistribution.co.uk/acatalog/Power-supply-for-Spectrum-128---2A---3-PS_SPE3.html|archive-date=29 August 2016}}</ref>

Significant alterations caused a series of incompatibilities, such as the removal of several lines on the expansion bus edge connector. This resulted in complications for various peripherals. Additionally, changes in memory timing led to certain RAM banks being contended, causing failures in high-speed colour-changing effects. The keypad scanning routines from the ROM were also eliminated, rendering some older 48K and 128K games incompatible with the machine. The ZX Interface 1 was also rendered incompatible due to disparities in ROM and expansion connectors, making it impossible to connect and use the Microdrive units.<ref name="Goodwin-145">{{Cite magazine| last= Goodwin |first= Simon |date=December 1987 |title= Tech Tips – +3 Faults |magazine= [[Crash (magazine)|Crash]] |issue= 48 |page= 145 |url=https://archive.org/details/Crash_Magazine_048b/page/144|access-date=24 April 2024}}</ref>

Production of the +3 was discontinued in December 1990, reportedly in response to Amstrad's relaunch of their CPC range, with an estimated 15% of ZX Spectrums sold being +3 models at the time. The +2B model, the only other model still in production at this point, continued to be manufactured, as it was believed not to be in direct competition with other computers in Amstrad's product range.<ref>{{cite news|title=Amstrad Kills Plus 3|url=https://archive.org/stream/crash-magazine-82/Crash_82_Nov_1990#page/n19/mode/2up|access-date=6 March 2018|work=Crash|issue=82|publisher=Newsfield|date=November 1990}}</ref><ref>{{cite news|title=Death Of The +3|url=https://archive.org/stream/your-sinclair-60/YourSinclair_60_Dec_1990#page/n9/mode/2up|access-date=6 March 2018|work=Your Sinclair|issue=60|publisher=Future Publishing|date=December 1990|url-status=live|archive-url=https://web.archive.org/web/20160610135431/http://archive.org/stream/your-sinclair-60/YourSinclair_60_Dec_1990#page/n9/mode/2up|archive-date=10 June 2016}}</ref>

=== ZX Spectrum +2A, +2B and +3B ===
[[file:Spectrum 128-2 (retouched).jpg|thumb|ZX Spectrum +2A]]

The ZX Spectrum +2A was a new version of the Spectrum +2<ref name='crashfeb89'>{{cite magazine|title=Dishy New Spectrum in Sex Scandal|magazine=Crash|issue=26|publisher=Newsfield|date=26 January 1989|page=9|url=https://spectrumcomputing.co.uk/page.php?issue_id=1028&page=7|access-date=26 November 2022}}{{Dead link|date=February 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> using the same circuit board as the Spectrum +3.<ref name='crashfeb89' /><ref name='nce101288'>{{cite magazine|title=Amstrad again|magazine=New Computer Express|issue=5|publisher=Future Publishing|date=10 December 1988|page=55|url=https://spectrumcomputing.co.uk/page.php?issue_id=4777&page=55|access-date=26 November 2022|archive-date=8 August 2020|archive-url=https://web.archive.org/web/20200808064929/https://spectrumcomputing.co.uk/page.php?issue_id=4777&page=55|url-status=dead}}</ref> It was sold from late 1988 and unlike the original grey +2 was housed inside a black case.<ref name='crashfeb89' /><ref name='nce101288' /> The Spectrum +2A/+3 motherboard (AMSTRAD part number Z70830) was designed so that it could be assembled with a +2 style "datacorder" connected instead of the [[floppy disk controller]].<ref name="+3-Manual-18">''Spectrum +3 Service Manual''. AMSTRAD. p.18.</ref> The power supply of the ZX Spectrum +2A used the same [[pinout]] as the +3 and has "Sinclair +2" written on the case.<ref name="Fuente+2A">{{cite web|url=http://hardware.speccy.org/hardware/Fuente+2A/imagenes/vista_superior.jpg|title=Image of Spectrum +2A power supply|access-date=21 December 2012|url-status=live|archive-url=https://web.archive.org/web/20130430080452/http://hardware.speccy.org/hardware/Fuente+2A/imagenes/vista_superior.jpg|archive-date=30 April 2013}}</ref>

1989 saw the release of the ZX Spectrum +2B and ZX Spectrum +3B. They are functionally similar in design to the Spectrum +2A and +3,<ref>''Spectrum +2B/+3B Service Manual''. AMSTRAD.</ref> though changes to the generation of the audio output signal were made to resolve problems with [[Clipping (audio)|clipping]].<ref name='nce090989'>{{cite magazine|title=Spex – Sounding Out|magazine=New Computer Express|issue=44|publisher=Future Publishing|date=9 September 1989|page=54|url=https://spectrumcomputing.co.uk/page.php?issue_id=4816&page=54|access-date=26 November 2022}}{{Dead link|date=February 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> The +2B board has no provision for floppy disk controller circuitry, while the +3B motherboard has no provision for connecting an internal tape drive. Production of all Amstrad Spectrum models ended in 1992.<ref name="bbclegacy" />

== Licences and clones ==
{{See also|List of ZX Spectrum clones}}

=== Official licences ===
[[File:Timex Sinclair 2068 Manipulated.jpg|thumb|[[Timex Sinclair 2068]], released in 1983 for the American market]]
Sinclair Research granted a licence for the ZX Spectrum design to the [[Timex Group USA|Timex Corporation]] in the United States. Timex marketed several computer models under the [[Timex Sinclair]] brand. They introduced an enhanced variant of the original Spectrum in the US, known as the [[Timex Sinclair 2068]]. This upgraded model features improvements in sound, graphics, and various other aspects. However, Timex's versions were generally not compatible with Sinclair systems.

[[File:Timex-Computer-2048-Manipulated.jpg|thumb|[[Timex Computer 2048]], highly compatible with the ZX Spectrum 48K, was very successful in both Portugal and Poland.]]

[[Timex of Portugal]] developed and produced several branded computers, including a [[PAL region]]-compatible version of the Timex Sinclair 2068, known as the [[Timex Computer 2048]]. This variant features distinct buffers for both the ULA and the CPU, significantly enhancing compatibility with ZX Spectrum software compared to the American model.<ref>{{cite web|url=https://timex.comboios.info/tc2068.html|title=Timex Computer 2068 specifications|work=Timex Computer World|access-date=13 December 2023|archive-date=13 December 2023|archive-url=https://web.archive.org/web/20231213151509/https://timex.comboios.info/tc2068.html|url-status=live}}</ref><ref>{{cite web|url=https://timex.comboios.info/tc2048.html|title=Timex Computer 2048 specifications|work=Timex Computer World|access-date=13 December 2023|archive-date=13 December 2023|archive-url=https://web.archive.org/web/20231213151509/https://timex.comboios.info/tc2048.html|url-status=live}}</ref> Software developed for the Portuguese-made 2048 remained fully compatible with its American counterpart, as the ROMs were left unaltered. Timex of Portugal also created a ZX Spectrum "emulator" in cartridge form.<ref>{{cite web |title=Timex Computer 2068 Emulator Cartridge specs |url=http://www.worldofspectrum.org/infoseekid.cgi?id=1000935 |website=World of Spectrum |access-date=5 May 2024 |archive-url=https://web.archive.org/web/20180828152540/http://www.worldofspectrum.org/infoseekid.cgi?id=1000935 |archive-date=28 August 2018}}</ref> Several other upgrades were introduced, including a BASIC64 cartridge enabling it to utilise high-resolution (512x192) modes.<ref>{{cite web |title=Timex command cartridges |url=https://loadzx.com/timexcomputerworld/timex-cartridge/ |website=LoadZX |access-date=5 May 2024 |archive-date=25 March 2024 |archive-url=https://web.archive.org/web/20240325172111/https://loadzx.com/timexcomputerworld/timex-cartridge/ |url-status=live }}</ref> This model saw significant success in both Portugal and Poland.<ref>{{cite web|url=http://www.old-computers.com/museum/computer.asp?st=1&c=935|title=Timex Computer 2048 overview|work=Old Computers|access-date=26 February 2017|url-status=live|archive-url=https://web.archive.org/web/20170227153005/http://www.old-computers.com/museum/computer.asp?st=1&c=935|archive-date=27 February 2017}}</ref>

[[File:SAM Coupé (white bg and shadow).jpg|thumb|The [[SAM Coupé]], despite being a commercial failure, is hailed as a credible successor to the ZX Spectrum.]]

In India, Deci Bells Electronics Limited<ref>{{Cite web |title=Deci Bells Electronics Limited Company Profile|url=https://economictimes.indiatimes.com/company/ |access-date=18 December 2022 |website=The Economic Times of India |language=en |archive-date=8 May 2019 |archive-url=http://webarchive.loc.gov/all/20190508200151/https://economictimes.indiatimes.com/company/ |url-status=dead }}</ref> based in [[Pune]], introduced a licensed version of the Spectrum+ in 1988.<ref>{{Cite web |title=deciBells dB Spectrum+ – Sinclair Collection |url=https://www.sinclaircollection.site/?page_id=455 |access-date=18 December 2022 |archive-date=6 October 2023 |archive-url=https://web.archive.org/web/20231006185743/https://www.sinclaircollection.site/?page_id=455 |url-status=live }}</ref><ref>{{Cite web |title=dB Spectrum+ at Spectrum Computing - Sinclair ZX Spectrum games, software and hardware |url=https://spectrumcomputing.co.uk/entry/1000517/Hardware/dB_Spectrum |access-date=18 December 2022 |website=Spectrum Computing |language=en }}</ref><ref>{{Cite web |title=The innovative legacy of Clive Sinclair |url=https://www.theweek.in/news/sci-tech/2021/09/18/the-innovative-legacy-of-clive-sinclair.html |access-date=18 December 2022 |website=The Week |language=en |archive-date=18 December 2022 |archive-url=https://web.archive.org/web/20221218234336/https://www.theweek.in/news/sci-tech/2021/09/18/the-innovative-legacy-of-clive-sinclair.html |url-status=live }}</ref> Dubbed the "dB Spectrum+", it performed well in the Indian market, selling over 50,000 units and achieving an 80% market share.<ref>{{Cite web |title=Tirlochan Singh |url=https://isourcingindia.com/team/tirlochan-singh/ |access-date=18 December 2022 |website=isourcingindia |language=en-US |archive-date=18 December 2022 |archive-url=https://web.archive.org/web/20221218234337/https://isourcingindia.com/team/tirlochan-singh/ |url-status=live }}</ref>

=== Unofficial clones ===
Numerous [[List of ZX Spectrum clones|unofficial Spectrum clones]] were produced, especially in Eastern Europe. Many small start-ups in the [[Soviet Union]] assembled various clones, distributed through poster adverts and street stalls. Over 50 such clone models existed in total.<ref>{{cite web |url= http://www.nvg.org/sinclair/computers/clones/clones.htm |title= Clones and variants |access-date= 26 October 2006 |last= Owen |first= Chris |work= Planet Sinclair |archive-date= 25 September 2006 |archive-url= https://web.archive.org/web/20060925001540/http://www.nvg.org/sinclair/computers/clones/clones.htm |url-status= live }}</ref> In [[Czechoslovakia]], the first production ZX Spectrum clone was  the [[Didaktik|Didaktik Gama]], sporting two [[Bank switching|switched]] 32&nbsp;KB memory banks and 16&nbsp;KB of slower RAM containing graphical data for video output, followed by [[Didaktik]] M, with later availability of a 5.25"/3.5" [[floppy disk]] drives; and a [[Didaktik]] Kompakt clone with a built-in floppy drive.<ref>{{Cite web |last=Slabihoud |first=Stephan |date=2000 |title=The PCB-Gallery - Didaktik Gamma |url=https://www.8bit-museum.de/pcb/index.htm?group=35&id=185 |access-date=2023-01-17 |website=8bit-museum.de |archive-date=30 September 2023 |archive-url=https://web.archive.org/web/20230930100727/https://8bit-museum.de/pcb/index.htm?group=35&id=185 |url-status=live }}</ref> There were also clones produced in South America, such as the Brazilian-made [[TK90X]] and [[TK95]],{{sfn|Penix-Tadsen|2019|p=14-16}} as well as the Argentine [[Czerweny computers|Czerweny CZ]] models.<ref>{{cite web |last=Zangoni |first=Néstor |date=2005-01-07 |title=CZERWENY Series (CZ) Argentina (Z80A) |url=https://microhobby.speccy.cz/290803/ord/tadeo.htm |access-date=2023-01-16 |website=MicroHobby Web independiente para usuarios de ordenadores Sinclair y compatibles |language=Spanish |archive-date=5 April 2024 |archive-url=https://web.archive.org/web/20240405171243/https://microhobby.speccy.cz/290803/ord/tadeo.htm |url-status=live }}</ref>

In the United Kingdom, Spectrum peripheral vendor [[Miles Gordon Technology]] (MGT) released the [[SAM Coupé]] 8-bit home computer in December 1989. It was designed to be fully compatible with the ZX Spectrum 48K, housing a Zilog Z80B processor clocked at 6&nbsp;MHz and 256KB of RAM.{{sfn|Leigh|2018|p=140}} By this point, the [[Amiga]] and [[Atari ST]] had taken hold of the market, leaving MGT in eventual receivership in June 1990.<ref>{{cite journal|last=Alway|first=Robin|title=So what really has happened to the SAM Coupé?|journal=[[Your Sinclair]]|issue=56|page=40|url=http://www.ysrnry.co.uk/articles/samsurgeon0890.htm|access-date=21 December 2012|url-status=dead|archive-url=https://web.archive.org/web/20130315073401/http://www.ysrnry.co.uk/articles/samsurgeon0890.htm|archive-date=15 March 2013}}</ref> In his book ''Retro Tech'', [[Nostalgia Nerd|Peter Leigh]] considers the Sam Coupé to be the "true" successor of the ZX Spectrum.{{sfn|Leigh|2018|p=142}}

== Peripherals ==
{{ multiple image|total_width=600
| image1 = Sinclair.zx.thermal.printer.jpg||
| image2 = Zx interface 2.png|thumb|
| image3 = Zx interface 1.png|thumb|left|
| image4 = Sinclair ZX Microdrive White BG.jpg|thumb|
| footer = Official peripherals: [[ZX Printer]], [[ZX Interface 2]], [[ZX Interface 1]], and [[ZX Microdrive]]
}}

Several [[peripheral]]s were developed and marketed by Sinclair. The [[ZX Printer]], a small [[Spark printing|spark printer]], was already on the market upon the ZX Spectrum's release,<ref>{{cite web |url= http://www.nvg.ntnu.no/sinclair/computers/peripherals/zxprinter.htm |title= ZX Printer |access-date= 24 August 2006 |last= Owen |first= Chris |work= Planet Sinclair |url-status= live |archive-url= https://web.archive.org/web/20060924093548/http://www.nvg.ntnu.no/sinclair/computers/peripherals/zxprinter.htm |archive-date= 24 September 2006 }}</ref> as its [[Bus (computing)|computer bus]] was partially [[Backward compatibility|backward-compatible]] with that of its predecessor, the ZX81. It uses two electrically charged styli to burn away the surface of aluminium-coated paper to reveal the black underlay.{{sfn|Adamson|Kennedy|1986|p=107}}

The [[ZX Interface 1]] add-on module, launched in 1983, includes 8&nbsp;KB of ROM, an [[RS-232]] serial port, a proprietary [[local area network]] (LAN) interface known as ZX Net, and a port for connecting up to eight [[ZX Microdrive]]s&nbsp;– tape-loop cartridge storage devices released in July 1983, known for their speed, albeit with some reliability concerns.<ref>{{Cite journal |date= September 1983 |title= News: Some surprises in the Microdrive |journal= [[Sinclair User]] |issue= 18 |page= 15 |url= http://www.sincuser.f9.co.uk/018/news.htm |access-date= 29 August 2006 |url-status= dead |archive-url= https://web.archive.org/web/20060924093253/http://www.sincuser.f9.co.uk/018/news.htm |archive-date= 24 September 2006 }}</ref><ref>{{Cite journal |last= Adams |first= Stephen |date= October 1983 |title= Hardware World: Spectrum receives its biggest improvement |journal= [[Sinclair User]] |issue= 19 |pages= 27–29 |url= http://www.sincuser.f9.co.uk/019/hardwre.htm |access-date= 29 August 2006 |url-status= dead |archive-url= https://web.archive.org/web/20060924101328/http://www.sincuser.f9.co.uk/019/hardwre.htm |archive-date= 24 September 2006 }}</ref> Sinclair Research also introduced the [[ZX Interface 2]], which added two joystick ports and a [[ROM cartridge]] port.<ref>{{Cite journal |date= December 1983 |title= Hardware World: Sinclair cartridges may be out of step |journal= [[Sinclair User]] |issue= 21 |page= 35 |url= http://www.sincuser.f9.co.uk/021/hardwre.htm |access-date= 29 August 2006 |url-status= dead |archive-url= https://web.archive.org/web/20060924100919/http://www.sincuser.f9.co.uk/021/hardwre.htm |archive-date= 24 September 2006 }}</ref> Although the ZX Microdrives were initially greeted with good reviews,<ref>{{Cite journal |last=Frey |first=Franco |title=Epicventuring and Multiplayer Networking |journal=[[Crash (magazine)|CRASH]] |date=May 1984 |issue=4 |pages=46–47 |url=http://www.crashonline.org.uk/04/microdv.htm |access-date=11 August 2007 |url-status=live |archive-url=https://web.archive.org/web/20070816014620/http://crashonline.org.uk/04/microdv.htm |archive-date=16 August 2007 }}</ref> they never became a popular distribution method due to fears over cartridge quality and piracy.<ref>{{Cite journal |last=Foot |first=Cathy |title=Microdrive revisited |journal=CRASH |date=November 1985 |issue=22 |page=8 |url=http://www.crashonline.org.uk/22/opinion.htm |access-date=10 August 2006 |url-status=live |archive-url=https://web.archive.org/web/20060822201523/http://www.crashonline.org.uk/22/opinion.htm |archive-date=22 August 2006 }}</ref>

[[file:Kempston joystick interface.jpeg|thumb|left|The [[Kempston Micro Electronics#Interface|Kempston interface]], a third-party add-on for [[joystick]]s]]

Third-party hardware add-ons were available throughout the machine's life, including the [[Kempston Micro Electronics#Interface|Kempston joystick interface]],{{sfn|Wilkins|2015a|p=14}} the Morex Peripherals [[Centronics]]/RS-232 interface, the [[Currah]] Microspeech unit for speech synthesis,<ref>{{Cite journal |date= December 1983 |title= Hardware World: Clear speech from Currah module |journal= [[Sinclair User]] |issue= 21 |page= 40 |url= http://www.sincuser.f9.co.uk/021/hardwre.htm |access-date= 29 August 2006 |url-status= dead |archive-url= https://web.archive.org/web/20060924100919/http://www.sincuser.f9.co.uk/021/hardwre.htm |archive-date= 24 September 2006 }}</ref> [[Videoface]] Digitiser,<ref>{{Cite journal |last=Frey |first=Franco |date=February 1987 |title=Tech Niche: Videoface to Face |journal=[[Crash (magazine)|CRASH]] |issue=37 |pages=86–87 |url=http://www.worldofspectrum.org/showmag.cgi?mag=Crash/Issue37/Pages/Crash3700086.jpg |access-date=5 August 2008 |archive-date=25 August 2012 |archive-url=https://web.archive.org/web/20120825201008/http://www.worldofspectrum.org/showmag.cgi?mag=Crash/Issue37/Pages/Crash3700086.jpg |url-status=live }}</ref> the [[SpecDrum]] drum machine,<ref>{{Cite journal |last=Bates |first=Jon |date=April 1986 |title=Tech Niche: SpecDrum |journal=[[Crash (magazine)|CRASH]] |issue=27 |page=100 |url=http://www.crashonline.org.uk/27/specdrum.htm |access-date=9 August 2007 |url-status=live |archive-url=https://web.archive.org/web/20070815194429/http://crashonline.org.uk/27/specdrum.htm |archive-date=15 August 2007 }}</ref> and the [[Multiface]], a snapshot and disassembly tool from Romantic Robot.<ref>{{Cite journal |last=Frey |first=Franco |date=March 1986 |title=Tech Niche: Multifaceted device |journal=[[Crash (magazine)|CRASH]] |issue=36 |page=86 |url=http://www.worldofspectrum.org/showmag.cgi?mag=Crash/Issue26/Pages/Crash2600086.jpg |access-date=5 August 2008 |ref=none |archive-date=25 August 2012 |archive-url=https://web.archive.org/web/20120825201012/http://www.worldofspectrum.org/showmag.cgi?mag=Crash/Issue26/Pages/Crash2600086.jpg |url-status=live }}</ref> After the original ZX Spectrum's keyboard received criticism for its "dead flesh" feel,<ref name=bbclegacy/> external keyboards became popular.<ref>{{Cite journal |date= October 1984 |title= Hardware World: Emperor Looks Good |journal= [[Sinclair User]] |issue= 31 |page= 31 |url= http://www.sincuser.f9.co.uk/031/hardwre.htm |access-date= 30 October 2007 |url-status= dead |archive-url= https://web.archive.org/web/20071212133608/http://www.sincuser.f9.co.uk/031/hardwre.htm |archive-date= 12 December 2007 }}</ref> In 1983, DK'Tronics launched a Light Pen compatible with some drawing software.<ref>{{cite web |title=DK'Tronics Light Pen |url=https://spectrumcomputing.co.uk/entry/1000124/Hardware/DKTronics_Light_Pen |website=spectrumcomputing.co.uk |access-date=3 June 2023 |language=en |date=1983 }}{{Dead link|date=June 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

The Abbeydale Designers/[[Watford Electronics]] SPDOS and KDOS disk drive interfaces were bundled with office productivity software, including the [[Tasword]] word processor, Masterfile database, and [[Microsphere (software company)#Company history|Omnicalc]] spreadsheet.{{sfn|South|1984|p=61}} This bundle, along with OCP's Stock Control, Finance, and Payroll systems, introduced small businesses to streamlined computerised operations.{{sfn|Leigh|2018|p=70}} In 1987 and 1988, [[Miles Gordon Technology]] released the [[DISCiPLE]] and [[+D]] systems. These systems had the capability to store memory images as disk snapshots, allowing users to restore the Spectrum to its exact previous state. Both systems were compatible with the Microdrive command syntax, simplifying the porting of existing software.<ref>{{Cite journal |last=Frey |first=Franco |date=March 1987 |title=Tech Niche: Pure Gospel |journal=[[Crash (magazine)|CRASH]] |issue=38 |pages=82–83 |url=http://www.worldofspectrum.org/showmag.cgi?mag=Crash/Issue38/Pages/Crash3800082.jpg |access-date=5 August 2008 |archive-date=25 August 2012 |archive-url=https://web.archive.org/web/20120825201016/http://www.worldofspectrum.org/showmag.cgi?mag=Crash/Issue38/Pages/Crash3800082.jpg |url-status=live }}</ref>

In the mid-1980s, Telemap Group launched a fee-based service allowing ZX Spectrum users to connect their machines to the [[Micronet 800]] information provider via a Prism Micro Products VTX5000 modem. Micronet 800, hosted by [[Prestel]], provided news and information about microcomputers and offered a form of instant messaging and online shopping.<ref>{{cite journal|url=http://www.worldofspectrum.org/hardware/feat24.html|title=Prism VTX 5000|publisher=Home Computer Advanced Course|year=1984|url-status=live|archive-url=https://web.archive.org/web/20130105100602/http://www.worldofspectrum.org/hardware/feat24.html|archive-date=5 January 2013 |website=World of Spectrum }}</ref>

== Software ==
{{Main|ZX Spectrum software|List of ZX Spectrum games}}
{{Multiple image|align=right|total_width=500
| image1 = ZX Rebelstar 3.png
| image3 = ZX Laser Squad.png
| footer = Screenshots from ZX Spectrum games ''[[Rebelstar]]'' (1984) and ''[[Laser Squad]]'' (1988)
}}

Most Spectrum software was originally distributed on [[audio cassette tape]]s, intended to work with a normal domestic cassette recorder.{{sfn|Leigh|2018|p=68}}<ref>{{Cite book |last=Vickers |first=Steven |author2=Bradbeer, Robin |author-link=Steve Vickers (academia) |title=Sinclair ZX Spectrum: Introduction |url=http://www.worldofspectrum.org/ZXSpectrumIntroduction/contents.html |access-date=10 August 2007 |year=1982 |publisher=[[Sinclair Research Ltd]] |page=21 |chapter=6. Using the cassette recorder |chapter-url=http://www.worldofspectrum.org/ZXSpectrumIntroduction/chapter_six.html |url-status=live |archive-url=https://web.archive.org/web/20070806070638/http://www.worldofspectrum.org/ZXSpectrumIntroduction/contents.html |archive-date=6 August 2007 }}</ref> Software was mainly distributed through print media such as magazines and books.{{sfn|Leigh|2018|p=69}}<ref>{{cite web |url= http://www.users.globalnet.co.uk/~jg27paw4/type-ins/typehome.htm |last= Grimwood |first= Jim |title= The Type Fantastic |access-date= 16 September 2008 |url-status= live |archive-url= https://web.archive.org/web/20080708225859/http://www.users.globalnet.co.uk/%7Ejg27paw4/type-ins/typehome.htm |archive-date= 8 July 2008 }}</ref><ref>{{cite web |url= http://www.worldofspectrum.org/books.html |work= World of Spectrum |last= van der Heide |first= Martijn |title= Books |access-date= 17 September 2008 |url-status= live |archive-url= https://web.archive.org/web/20080928210007/http://www.worldofspectrum.org/books.html |archive-date= 28 September 2008 }}</ref> To load software onto the machine, the reader would [[type-in program|type the BASIC program listing by hand]], run it, and save it to the cassette for later use. Some magazines distributed 7" 33{{Fraction|1|3}} rpm [[flexi disc]] records, or "[[Floppy ROM]]s", a variant of regular [[vinyl record]]s which could be played on a standard record player.<ref>{{cite web |last1=Freeman |first1=Will |title=Spin machines: the curious history of video games on vinyl |url=https://www.theguardian.com/games/2021/jul/07/video-games-on-vinyl-flexi-discs-zx-spectrum |website=[[The Guardian]] |access-date=23 October 2023 |archive-url=https://web.archive.org/web/20230125135756/https://www.theguardian.com/games/2021/jul/07/video-games-on-vinyl-flexi-discs-zx-spectrum |archive-date=25 January 2023 |location=London |date=7 July 2021}}</ref> Some radio stations would broadcast audio stream data via [[frequency modulation]] or [[medium wave]] so that listeners could directly record it onto an audio cassette themselves. ZX Spectrum-focused radio programmes existed in the United Kingdom, which were received over long distances on domestic radio receivers.{{sfn|Gilbert|1983b|p=14}}

Different types of software released for the machine include [[programming language]] implementations, [[database]]s,<ref name="zappowboom">{{Cite journal |last=Pearce |first=Nick |date=October–November 1982 |title=Zap! Pow! Boom! |journal=ZX Computing |page=75 |url=http://www.worldofspectrum.org/showmag.cgi?mag=ZXComputing/Issue8210/Pages/ZXComputing821000075.jpg |access-date=5 August 2008 |archive-date=25 August 2012 |archive-url=https://web.archive.org/web/20120825201021/http://www.worldofspectrum.org/showmag.cgi?mag=ZXComputing/Issue8210/Pages/ZXComputing821000075.jpg |url-status=live }}</ref> [[word processor]]s (''[[Tasword]]'' being the most prominent{{sfn|Wetherill|1984|p=126}}), [[spreadsheet]]s,<ref name="zappowboom"/> drawing and painting tools (e.g. [[OCP Art Studio]]<ref>{{Cite journal |last=Gilbert |first=John |date=October 1985 |title=Art Studio |journal=Sinclair User |issue=43 |page=28 |url=http://www.sincuser.f9.co.uk/043/sftwreb.htm |access-date=18 January 2007 |url-status=dead |archive-url=https://web.archive.org/web/20060924103003/http://www.sincuser.f9.co.uk/043/sftwreb.htm |archive-date=24 September 2006 }}</ref>), 3D-modelling (e.g. VU-3D<ref>{{Cite journal |last=Carter |first=Alasdair |date=October–November 1983 |title=VU-3D |journal=ZX Computing |pages=76–77 |url=http://www.worldofspectrum.org/showmag.cgi?mag=ZXComputing/Issue8210/Pages/ZXComputing821000076.jpg |access-date=5 August 2008 |archive-date=25 August 2012 |archive-url=https://web.archive.org/web/20120825201025/http://www.worldofspectrum.org/showmag.cgi?mag=ZXComputing/Issue8210/Pages/ZXComputing821000076.jpg |url-status=live }}</ref><ref>{{cite web |url=http://www.bioeddie.co.uk/Spectrum/vu-3d.htm |title=Psion Vu-3D |access-date=18 January 2007 |url-status=live |archive-url=https://web.archive.org/web/20070202125355/http://bioeddie.co.uk/Spectrum/vu-3d.htm |archive-date=2 February 2007 }}</ref>) and [[archaeology]] software.<ref>{{cite web |url= http://www.pitcalc.com/ |last= Brown |first= Paul N. |title= Pitcalc&nbsp;— simple interactive coordinate & trigonometric calculation software |access-date= 16 September 2008 |url-status= live |archive-url= https://web.archive.org/web/20081206033912/http://www.pitcalc.com/ |archive-date= 6 December 2008 }}</ref> Over 24,000 different software titles were released for the ZX Spectrum throughout its lifespan.<ref name=BT/> The ZX Spectrum had an extensive library of video games, including iconic titles such as ''[[Manic Miner]]'', ''[[Jet Set Willy]]'', ''[[Chuckie Egg]]'', ''[[Elite (video game)|Elite]]'', ''[[Sabre Wulf]]'', ''[[Knight Lore]]'', and ''[[The Hobbit (1982 video game)|The Hobbit]]''. Many of the popular ZX81 titles were rewritten for the Spectrum to take advantage of the newer machine's colour and sound capabilities (Psion's ''[[Flight Simulation (Psion software)|Flight Simulation]]'' being a notable example). These games were instrumental in establishing the machine as a prominent gaming platform during the 1980s. Hardware limitations of the machine required a level of creativity from [[video game designer]]s.{{sfn|Adamson|Kennedy|1986|p=64}}<ref>{{Cite news |last= McCandless |first= David |title= Retrospectrum |newspaper= The Daily Telegraph |date= 17 September 1998 |url= http://www.nvg.ntnu.no/sinclair/sinclair/clive_dt170998.htm |url-status= live |archive-url= https://web.archive.org/web/20091016033400/http://www.nvg.ntnu.no/sinclair/sinclair/clive_dt170998.htm |archive-date= 16 October 2009 }}</ref> From August 1982 the ZX Spectrum came bundled with ''[[Horizons: Software Starter Pack]]'',<ref name="psion-ssp">{{Cite AV media notes | title = Psion Horizons Software starter pack | year = 1982 | type = Cassette inlay | publisher = Psion }}</ref> a software compilation which included ten demonstration programs.{{sfn|Kelly|1982|p=5}}

Some ZX Spectrum games hold a number of industry-firsts and [[Guinness World Records]]. These include ''[[Ant Attack]]'', the first computer game to use [[Isometric video game graphics|isometric graphics]],<ref>{{cite web |title=First isometric home computer game |url=https://www.guinnessworldrecords.com/world-records/105280-first-isometric-home-computer-game |publisher=[[Guinness World Records]] |access-date=21 October 2023 |archive-url=https://web.archive.org/web/20231021183708/https://www.guinnessworldrecords.com/world-records/105280-first-isometric-home-computer-game |archive-date=21 October 2023}}</ref> ''[[Turbo Esprit]]'', the first [[open world game|open world]] driving game,<ref>{{cite web |title=First open-world driving videogame |url=https://www.guinnessworldrecords.com/world-records/first-driving-game-to-feature-an-open-world-environment |publisher=[[Guinness World Records]] |access-date=21 October 2023 |archive-url=https://web.archive.org/web/20220826135350/https://www.guinnessworldrecords.com/world-records/first-driving-game-to-feature-an-open-world-environment |archive-date=26 August 2022}}</ref> and ''Redhawk'', which featured the first superhero created specifically for a video game.<ref>{{cite web |title=First superhero created for a videogame |url=https://www.guinnessworldrecords.com/world-records/89121-first-superhero-created-for-a-videogame |publisher=[[Guinness World Records]] |access-date=21 October 2023 |archive-url=https://web.archive.org/web/20231021184047/https://www.guinnessworldrecords.com/world-records/89121-first-superhero-created-for-a-videogame |archive-date=21 October 2023}}</ref>

[[file:Psion Horizons for ZX Spectrum cassette.jpg|thumb|Spectrum software was distributed almost exclusively on audio cassettes.]]

== Reception ==
Initial reception of the ZX Spectrum was generally positive. Critics in Britain welcomed the new machine as a worthy successor to the [[ZX81]]; Robin Bradbeer of ''[[Sinclair User]]'' praised the additional keyboard functions the Spectrum had to offer, and lauded the "strength" of its ergonomic and presentable design.{{sfn|Bradbeer|1982|pp=14-15}} [[Tim Hartnell]] from ''[[Your Computer (British magazine)|Your Computer]]'' noted that Sinclair had improved on the shortcomings of the [[ZX80]] and ZX81 by revamping the Spectrum's load and save functions, noting that it made working with the machine "a pleasure".{{sfn|Hartnell|1982|pp=20-21}} Hartnell concluded that despite minor faults, the machine was "way ahead" of its competitors, and its specification exceeded that of the [[BBC Micro]] Model A.{{sfn|Hartnell|1982|p=22}}

''[[Computer and Video Games]]''{{'}} Terry Pratt compared the Spectrum's keyboard negatively to the typewriter-style used on the BBC Micro, opining that it was an improvement over the ZX81 but unsuited for "typists".{{sfn|Pratt|1982b|p=3}} In similar vein, David Tebbutt from ''[[Personal Computer World]]'' felt that the Spectrum's keyboard felt more like a calculator than typewriter, but praised its functional versatility.{{sfn|Tebbutt|1982|p=118}} Likewise, Gregg Williams from ''[[Byte (magazine)|BYTE]]'' criticised the keyboard, declaring that despite the machine's attractive price the layout "is impossible to justify" and "poorly designed" in several respects. Williams was sceptical of the computer's appeal to American consumers if sold for {{US$|220}}&nbsp;– "hardly competitive with comparable low-cost American units"&nbsp;– and expected that Timex would sell it for {{val|p=$|125|–|150}}.{{sfn|Williams|1983|p=40}} A more negative review came from Jim Lennox of ''Technology Week'', who wrote that "after using it&nbsp;[...] I find Sinclair's claim that it is the most powerful computer under £500 unsustainable. Compared to more powerful machines, it is slow, its colour graphics are disappointing, its BASIC limited and its keyboard confusing".<ref name="nerd"/>

== Legacy ==
{{Quote box
|quote = "You cannot exaggerate Sir [[Clive Sinclair]]’s influence on the world [...] All your UK video game companies today were built on the shoulders of giants who made games for the ZX Spectrum."|source = — Television presenter [[Dominik Diamond]] on Sinclair's death in 2021.<ref>{{cite web |title=Video games industry mourns death of ZX Spectrum creator Sir Clive Sinclair |url=https://metro.co.uk/2021/09/16/games-industry-mourns-death-of-zx-spectrum-creator-sir-clive-sinclair-15271911/ |website=The Metro |publisher=Associated Newspapers Limited |access-date=10 October 2023 |archive-url=https://web.archive.org/web/20220605094352/https://metro.co.uk/2021/09/16/games-industry-mourns-death-of-zx-spectrum-creator-sir-clive-sinclair-15271911/ |archive-date=5 June 2022 |location=London |language=en |date=16 September 2021}}</ref>|width = 30em}}

The importance of the ZX Spectrum and its role in the early [[History of personal computers|history of personal computing]] and [[history of video gaming|video gaming]] has left it regarded as the most important and influential computer of the 1980s.{{sfn|Leigh|2018|p=69}}<ref name=bbclegacy/><ref name="tech40">{{cite web |last1=Casserly |first1=Martyn |title=ZX Spectrum: 40 Years of the Punk Rock PC |url=https://www.techadvisor.com/article/746263/zx-spectrum-at-40-why-its-the-most-important-computer-in-history.html |website=[[Tech Advisor]] |publisher=[[IDG Entertainment]] |access-date=26 October 2023 |archive-url=https://web.archive.org/web/20230130170959/https://www.techadvisor.com/article/746263/zx-spectrum-at-40-why-its-the-most-important-computer-in-history.html |archive-date=30 January 2023 |language=en |date=26 April 2022}}</ref> Some observers credit it as being responsible for launching the British information technology industry during [[early 1980s recession|a period of recession]],<ref name="reg25">{{cite web |last=Williams |first=Chris |url=http://www.reghardware.co.uk/2007/04/23/spectrum_zx_25/ |title=Sinclair ZX Spectrum: 25 today |website=The Register|location=London |access-date=14 September 2008 |date=23 April 2007 |publisher=Situation Publishing |url-status=live |archive-url=https://web.archive.org/web/20180718174459/https://www.theregister.co.uk/2007/04/23/spectrum_zx_25/ |archive-date=18 July 2018 }}</ref> while introducing home computing to the masses.<ref>{{cite web |last1=Jowitt |first1=Tom |title=Tales In Tech History: ZX Spectrum |url=https://www.silicon.co.uk/workspace/pc/tales-tech-history-zx-spectrum-207004 |website=Silicon UK |publisher=NetMedia International |access-date=20 May 2024 |location=London |date=10 March 2017}}</ref> {{As of|2024}}, it is also one of the best-selling British computers of all time, with over five million units sold by the end of the Spectrum's lifespan in 1992.<ref name="backlash" /><ref name="slice" /> It retained the title of Britain's top-selling computer until the [[Amstrad PCW]] surpassed it in the 1990s, with eight million units sold by the end of the PCW's lifespan in 1998.<ref name="typewriter" /><ref name="slice" /> The ZX Spectrum is affectionately known as the "Speccy" by elements of its fan following.<ref name="ys-70">{{Cite journal |date= October 1991 |title= The YS Top 100 Speccy Games Of All Time (Ever!) |journal= [[Your Sinclair]] |issue= 70 |page= 31 |url= http://www.ysrnry.co.uk/articles/ystop100.htm |access-date= 13 June 2007 |url-status= dead |archive-url= https://web.archive.org/web/20060816053829/http://www.ysrnry.co.uk/articles/ystop100.htm |archive-date= 16 August 2006 }}</ref>

The ZX Spectrum was popular in communist [[Czechoslovakia]], with an estimated 100,000 in the country by 1988 making it the most popular home computer of the time. This was despite only briefly being officially distributed, and never advertised. Its small size made it easier to smuggle into the country to avoid high customs fees.<ref>{{Cite book |last=Švelch |first=Jaroslav |url=https://books.google.com/books?id=XWB9DwAAQBAJ |title=Gaming the Iron Curtain: how teenagers and amateurs in Communist Czechoslovakia claimed the medium of computer games |date=2018 |publisher=MIT Press |isbn=978-0-262-03884-3 |series=Game Histories |location=Cambridge, Massachusetts |pages=47–49}}</ref>

A number of notable games developers began their careers on the ZX Spectrum. [[Tim and Chris Stamper]] founded [[Ultimate Play the Game]] in 1982,{{sfn|Hunt|2010|p=24}} who found success with their blockbuster hits ''[[Jetpac]]'' (1983), ''[[Atic Atac]]'' (1983), ''[[Sabre Wulf]]'' (1984), and ''[[Knight Lore]]'' (1984).{{sfn|Hunt|2010|pp=24–31}} The Stamper brothers later founded [[Rare (company)|Rare]], which became [[Nintendo]]'s first Western third-party developer.<ref>{{Cite web|last1=McLaughlin |first1=Rus |title=IGN Presents the History of Rare |website=[[IGN]]|publisher=[[Ziff Davis]]|location=Chicago|date=28 July 2008 |url=http://www.ign.com/articles/2008/07/28/ign-presents-the-history-of-rare |access-date=30 May 2017 |url-status=live |archive-url=https://web.archive.org/web/20160810005739/http://www.ign.com/articles/2008/07/28/ign-presents-the-history-of-rare |archive-date=10 August 2016 }}</ref> [[David Perry (game developer)|David Perry]], the founder of [[Shiny Entertainment]], moved from Northern Ireland to England to focus on developing games for the ZX Spectrum.<ref>{{cite web |title=David Perry of Shiny |url=https://www.eurogamer.net/dperry |website=[[Eurogamer]] |publisher=[[Future plc]] |access-date=25 October 2023 |archive-url=https://web.archive.org/web/20220523024139/https://www.eurogamer.net/dperry |archive-date=23 May 2022 |location=[[Bath, Somerset|Bath]] |language=en |date=20 October 1999}}</ref>

Some programmers have continued to code for the platform by using emulators.<ref name="Kelion">{{Cite news |last=Kelion |first=Leo |date=23 April 2012 |title=Sinclair's ZX Spectrum turns 30 |url=https://www.bbc.com/news/technology-17776666 |url-status=live |archive-url=https://web.archive.org/web/20190629131805/https://www.bbc.com/news/technology-17776666 |archive-date=29 June 2019 |access-date=15 July 2019 |work=BBC News}}</ref> A [[Homebrew (video games)|homebrew]] community continues into the present day, with several games being released commercially from new software houses such as [[Cronosoft]].<ref>{{cite web |title=About us - What we do |url=https://cronosoft.fwscart.com/storepage5357726.aspx |archive-url=https://web.archive.org/web/20230920062525/https://cronosoft.fwscart.com/storepage5357726.aspx |archive-date=20 September 2023 |access-date=21 October 2023 |publisher=[[Cronosoft]]}}</ref> In 2020, a museum dedicated to the ZX Spectrum and other Sinclair products opened in [[Cantanhede, Portugal|Cantanhede]], Portugal.<ref name="loadzx">{{Cite web |title=LOAD ZX Spectrum |url=https://www.loadzx.com/en/ |url-status=live |archive-url=https://web.archive.org/web/20201022065054/https://loadzx.com/en/ |archive-date=22 October 2020 |access-date=19 October 2020}}</ref>

=== Recreations ===
In 2013, an [[FPGA]]-based [[List_of_ZX_Spectrum_clones#PLD-based_clones|clone]] known as the [[ZX-Uno|ZX Uno]], was formally announced. All of its hardware, firmware and software are [[open source]],<ref>{{Cite web|last=By|date=13 January 2017|title=Retro ZX Spectrum Lives A Spartan Existence|url=https://hackaday.com/2017/01/12/retro-zx-spectrum-lives-a-spartan-existence/|access-date=30 July 2020|website=Hackaday|language=en-US|archive-date=25 July 2020|archive-url=https://web.archive.org/web/20200725020214/https://hackaday.com/2017/01/12/retro-zx-spectrum-lives-a-spartan-existence/|url-status=live}}</ref> released as [[Creative Commons licence]] Share-alike. The use of a [[Spartan (FPGA)|Spartan]] FPGA allows the system to not only re-implement the ZX Spectrum, but many other 8-bit computers and games consoles.<ref>{{Cite web|title=Back this Crowdfunding "ZX-UNO" in Verkami|url=https://www.verkami.com/projects/14074-zx-uno|access-date=30 July 2020|website=www.verkami.com|language=en|archive-date=5 September 2020|archive-url=https://web.archive.org/web/20200905095017/https://www.verkami.com/projects/14074-zx-uno|url-status=live}}</ref> The Uno was successfully [[crowdfunding|crowdfunded]] in 2016 and the first boards went on sale the same year.<ref>{{cite web|url=http://zxuno.speccy.org/index_e.shtml|title=ZX-Uno|access-date=20 February 2018|url-status=live|archive-url=https://web.archive.org/web/20180105191835/http://zxuno.speccy.org/index_e.shtml|archive-date=5 January 2018}}</ref>

In January 2014, [[Elite Systems]], who produced a successful range of software for the original ZX Spectrum in the 1980s, announced plans for a Spectrum-themed [[bluetooth]] keyboard that would attach to mobile devices.<ref>{{cite news|url=https://www.theregister.co.uk/2014/01/29/sinclairs_zx_spectrum_to_live_again/|title=Sinclair's ZX Spectrum to LIVE AGAIN!|first=Simon|last=Sharwood|work=The Register|date=29 January 2014|access-date=31 January 2014|url-status=live|archive-url=https://web.archive.org/web/20140131073309/http://www.theregister.co.uk/2014/01/29/sinclairs_zx_spectrum_to_live_again/|archive-date=31 January 2014}}</ref><ref>{{cite news|url=http://www.techradar.com/news/gaming/zx-spectrum-is-coming-back-as-a-bluetooth-keyboard-1211655|title=ZX Spectrum is coming back as a Bluetooth keyboard|first=Alex|last=Hamilton|work=TechRadar|date=2 January 2014|access-date=31 January 2014|url-status=live|archive-url=https://web.archive.org/web/20140204231450/http://www.techradar.com/news/gaming/zx-spectrum-is-coming-back-as-a-bluetooth-keyboard-1211655|archive-date=4 February 2014}}</ref> The company used a crowdfunding campaign to fund the ''Recreated ZX Spectrum'', which would be compatible with games the company had already released on [[iTunes]] and [[Google Play]].<ref>{{cite news|url=https://www.telegraph.co.uk/technology/news/10546696/ZX-Spectrum-to-be-resurrected-as-Bluetooth-keyboard.html|title=ZX Spectrum to be resurrected as Bluetooth keyboard|first=Sophie|last=Curtis|work=[[The Daily Telegraph]]|date=2 January 2014|access-date=31 January 2014|url-status=live|archive-url=https://web.archive.org/web/20140106031043/http://www.telegraph.co.uk/technology/news/10546696/ZX-Spectrum-to-be-resurrected-as-Bluetooth-keyboard.html|archive-date=6 January 2014}}</ref> Elite Systems took down its Spectrum Collection application the following month, due to complaints from authors of the original software that they had not been paid for the content.<ref>{{cite news |author=Alex Hern |url=https://www.theguardian.com/technology/gamesblog/2014/feb/13/zx-spectrum-kickstarter-over-unpaid-developer-bills |title=ZX Spectrum Kickstarter project stalls over unpaid developer bills |newspaper=The Guardian |access-date=26 June 2015 |url-status=live |archive-url=https://web.archive.org/web/20150627035003/http://www.theguardian.com/technology/gamesblog/2014/feb/13/zx-spectrum-kickstarter-over-unpaid-developer-bills |archive-date=27 June 2015 }}</ref> ''[[Wired UK]]'' described the finished device, which was styled as an original Spectrum 48k keyboard, as "absolutely gorgeous" but said it was ultimately more of an expensive novelty than an actual Spectrum.<ref name="Rundle">{{Cite magazine|last=Rundle|first=Michael|date=1 October 2015|title=Which of the 'retro' Spectrum remakes is worth your £100?|language=en-GB|magazine=[[Wired UK]]|publisher=[[Condé Nast]]|location=New York City|url=https://www.wired.co.uk/article/recreated-spectrum-zx-vega-review|access-date=30 July 2020|issn=1357-0978|archive-date=4 September 2020|archive-url=https://web.archive.org/web/20200904141917/https://www.wired.co.uk/article/recreated-spectrum-zx-vega-review|url-status=live}}</ref> In July 2019, ''[[Eurogamer]]'' reported that many of the orders had yet to be delivered due to a dispute between Elite Systems and their manufacturer, Eurotech.<ref>{{Cite web|last=Yin-Poole|first=Wesley|date=8 July 2016|title=When Kickstarters go bad: chasing down the Recreated ZX Spectrum|url=https://www.eurogamer.net/articles/2016-07-08-when-kickstarters-go-bad-chasing-down-the-recreated-zx-spectrum|access-date=30 July 2020|website=[[Eurogamer]]|publisher=[[Future plc]]|location=[[Bath, Somerset|Bath]]|language=en|archiveurl=https://web.archive.org/web/20231011181505/https://www.eurogamer.net/when-kickstarters-go-bad-chasing-down-the-recreated-zx-spectrum|archivedate=11 October 2023}}</ref>

[[File:Sinclair ZX Spectrum Vega.png|thumb|The ZX Spectrum Vega TV Game Console, made by Retro Computers]]

Later in 2014, the [[ZX Spectrum Vega]] retro video game console was announced by Retro Computers and crowdfunded on [[Indiegogo]] with the backing of Clive Sinclair.<ref name=guardian20121202>{{cite news |author=Samuel Gibbs |url=https://www.theguardian.com/technology/2014/dec/02/zx-spectrum-vega-games-console |title=ZX Spectrum gets new lease of life as Vega games console |date=2 December 2014|newspaper=The Guardian |access-date=26 June 2015 |url-status=live |archive-url=https://web.archive.org/web/20150625225821/http://www.theguardian.com/technology/2014/dec/02/zx-spectrum-vega-games-console |archive-date=25 June 2015 }}</ref> The Vega, released in 2015, took the form of a [[handheld TV game]]<ref name=guardian20121202/><ref>{{cite web|url=https://www.telegraph.co.uk/men/the-filter/10547681/8-reasons-you-should-be-excited-about-the-return-of-the-ZX-Spectrum.html|title=8 reasons you should be excited about the return of the ZX Spectrum|author=Theo Merz|date=3 January 2014|work=The Daily Telegraph|archive-url=https://web.archive.org/web/20160323011350/http://www.telegraph.co.uk/men/the-filter/10547681/8-reasons-you-should-be-excited-about-the-return-of-the-ZX-Spectrum.html|archive-date=23 March 2016|url-status=live|access-date=28 April 2016}}</ref> but the lack of a full keyboard<ref name=syntax>{{cite news|last=Kelion|first=Leo|date=2 December 2014|title=Syntax era: Sir Clive Sinclair's ZX Spectrum revolution|work=BBC News|url=https://www.bbc.co.uk/news/technology-30333671|url-status=live|access-date=8 December 2014|archive-url=https://web.archive.org/web/20141207122843/http://www.bbc.co.uk/news/technology-30333671|archive-date=7 December 2014}}</ref> led to criticism from reviewers due to the large number of text adventures supplied with the device.<ref>{{Cite web|last=McFerran|first=Damien|title=ZX Spectrum Vega Review|url=https://www.trustedreviews.com/reviews/zx-spectrum-vega|access-date=30 July 2020|website=Trusted Reviews|date=16 September 2015|language=en|archive-date=5 September 2020|archive-url=https://web.archive.org/web/20200905014409/https://www.trustedreviews.com/reviews/zx-spectrum-vega|url-status=live}}</ref><ref>{{Cite web|title=Sinclair Vega|url=http://www.thespectrumshow.co.uk/Feature12.aspx|access-date=30 July 2020|website=www.thespectrumshow.co.uk|archive-date=12 August 2020|archive-url=https://web.archive.org/web/20200812162113/http://www.thespectrumshow.co.uk/Feature12.aspx|url-status=live}}</ref> Most reviewers branded the device cheap and uncomfortable to use.<ref>{{Cite web|title=ZX Spectrum Vega vs Recreated ZX Spectrum|url=https://www.stuff.tv/features/zx-spectrum-vega-vs-recreated-zx-spectrum/zx-spectrum-vega-ps100-pp|access-date=30 July 2020|website=Stuff|language=en|archive-date=3 August 2020|archive-url=https://web.archive.org/web/20200803180757/https://www.stuff.tv/features/zx-spectrum-vega-vs-recreated-zx-spectrum/zx-spectrum-vega-ps100-pp|url-status=dead}}</ref><ref name="Rundle"/> The follow-up, the [[ZX Spectrum Vega+]] was designed as a [[handheld game console]]. Despite reaching its crowdfunding target in March 2016,<ref>{{cite web|last1=Merriman|first1=Chris|title=ZX Spectrum Vega+ raises three times its Indiegogo target in three weeks|url=http://www.theinquirer.net/inquirer/news/2450038/zx-spectrum-vega-raises-three-times-its-indigogo-target-in-three-weeks|archive-url=https://web.archive.org/web/20160309104916/http://www.theinquirer.net/inquirer/news/2450038/zx-spectrum-vega-raises-three-times-its-indigogo-target-in-three-weeks|url-status=unfit|archive-date=9 March 2016|access-date=25 August 2016|website=The Inquirer|publisher=Incisive Business Media Limited}}</ref> the company failed to fulfil the majority of orders. Reviewing the Vega+, ''[[The Register]]'' criticised numerous aspects and features of the machine, including its design and build quality and summed up by saying that the "entire feel is plasticky and inconsequential".<ref>{{cite web|url=https://www.theregister.com/2018/08/09/zx_spectrum_vega_plus_hands_on_review/|title=ZX Spectrum Vega+ blows a FUSE: It runs open-source emulator|last1=Corfield|first1=Gareth|website=The Register|date=9 August 2018|access-date=5 July 2021|archive-date=22 June 2021|archive-url=https://web.archive.org/web/20210622013509/https://www.theregister.com/2018/08/09/zx_spectrum_vega_plus_hands_on_review/|url-status=live}}</ref> Retro Computers Ltd was placed into liquidation in 2019.<ref>{{cite web|last1=Corfield|first1=Gareth|title=Is this a wind-up?|url=https://www.theregister.co.uk/2019/02/05/retro_computers_ltd_wound_up_private_planet/|access-date=5 February 2019|website=The Register|publisher=Situation Publishing|date=5 February 2019|archive-date=5 February 2019|archive-url=https://web.archive.org/web/20190205212610/https://www.theregister.co.uk/2019/02/05/retro_computers_ltd_wound_up_private_planet/|url-status=live}}</ref>

The [[ZX Spectrum Next]] is an expanded and updated version of the ZX Spectrum computer implemented with FPGA technology<ref>{{cite web |title=About |url=https://www.specnext.com/about/ |website=Sinclair ZX Spectrum Next |date=29 April 2017 |access-date=13 February 2020 |archive-date=5 November 2023 |archive-url=https://web.archive.org/web/20231105135454/https://www.specnext.com/about/ |url-status=live }}</ref> funded by a [[Kickstarter]] campaign in April 2017,<ref>{{cite news|date=24 April 2017|title=Celebrate the Sinclair ZX Spectrum's 35th anniversary with… yet another retro console|newspaper=Metro (UK)|url=https://metro.co.uk/2017/04/24/celebrate-the-sinclair-zx-spectrums-35th-anniversary-with-yet-another-retro-console-6594446/|access-date=30 July 2020|archive-date=6 October 2023|archive-url=https://web.archive.org/web/20231006190020/https://metro.co.uk/2017/04/24/celebrate-the-sinclair-zx-spectrums-35th-anniversary-with-yet-another-retro-console-6594446/amp/|url-status=live}}</ref> with the board-only computer delivered to backers later that year.<ref>{{Cite web|url=https://www.specnext.com/instructions-for-the-2a-next-board/|title=Quick Start Guide / Instructions for the 2A/B Next boards|website=ZX Spectrum Next|date=3 December 2017 |access-date=15 May 2024|archive-date=29 March 2024|archive-url=https://web.archive.org/web/20240329112652/https://www.specnext.com/instructions-for-the-2a-next-board/|url-status=live}}</ref> The finished machine, including a case designed by [[Rick Dickinson]] who died during the development of the project,<ref>{{Citation|last=Rick Dickinson|title=specnext1.1157|date=28 September 2017|url=https://www.flickr.com/photos/9574086@N02/37361836341/|access-date=30 July 2020|archive-date=24 January 2022|archive-url=https://web.archive.org/web/20220124074656/https://www.flickr.com/photos/9574086@N02/37361836341/|url-status=live}}</ref> was released to backers in February 2020.<ref>{{cite web |title=First ZX Spectrum Next delivered |url=https://www.specnext.com/first-zx-spectrum-next-delivered/ |website=Sinclair ZX Spectrum Next |date=6 February 2020 |access-date=13 February 2020 |archive-date=30 May 2020 |archive-url=https://web.archive.org/web/20200530115336/https://www.specnext.com/first-zx-spectrum-next-delivered/ |url-status=live }}</ref> ''MagPi'' called it "a lovely piece of kit", noting that it is "well-designed and well-built: authentic to the original, and with technology that nods to the past while remaining functional and relevant in the modern age".<ref>{{cite news|last=Hattersley|first=Lucy|date=April 2020|title=ZX Spectrum Next Accelerated review|newspaper=MagPi Magazine|url=https://magpi.raspberrypi.org/articles/zx-spectrum-next-accelerated-review|access-date=30 July 2020|archive-date=25 July 2020|archive-url=https://web.archive.org/web/20200725062422/https://magpi.raspberrypi.org/articles/zx-spectrum-next-accelerated-review|url-status=live}}</ref> PC Pro magazine called the Next "undeniably impressive" while noting that some features are "not quite ready".<ref>{{cite news|last=Halfacree|first=Gareth|date=June 2020|title=ZX Spectrum Next|newspaper=PC Pro Magazine (UK)}}</ref> A further Kickstarter for an improved revision of the hardware was funded in August 2020.<ref name="bbc-news-2020-08-13">{{cite news |title=ZX Spectrum Next Issue 2 blasts through Kickstarter goal |url=https://www.bbc.co.uk/news/technology-53765852 |access-date=23 July 2021 |work=BBC News |date=13 August 2020 |archive-date=23 July 2021 |archive-url=https://web.archive.org/web/20210723092838/https://www.bbc.co.uk/news/technology-53765852 |url-status=live }}</ref>

The [[ZX Touch]] is a handheld gaming console, released by Elmar Electronic in November 2023, that uses [[Bare machine|bare-metal]] emulation to play ZX Spectrum games. It features a 7-inch touchscreen, built-in games, and microSD support for loading additional games.<ref>{{cite web |title=ZX Touch – ZX Spectrum handheld console |url=https://zx-touch.com/ |website=ZX Touch |access-date=12 April 2025 |language=en}}</ref>

In August 2024, Retro Games announced that they would be releasing a recreation of the ZX Spectrum titled "The Spectrum" which would include 48 built-in games, a save game option, rewind mode and pre-owned titles load up. It was released on 22 November 2024.<ref>{{Cite web |last=Games |first=Chris Smith, Retro |date=2024-01-11 |title=The Spectrum |url=https://retrogames.biz/products/thespectrum/ |access-date=2024-09-01 |website=retrogames.biz |language=en-us}}</ref><ref>{{Cite web |last=Reporter |first=Matt Wales News |date=2024-08-27 |title=ZX Spectrum recreation coming this November from team behind Atari 400 Mini, rubber keys and all |url=https://www.eurogamer.net/zx-spectrum-recreation-coming-from-team-behind-atari-400-mini-rubber-keys-and-all |access-date=2024-09-01 |website=Eurogamer.net |language=en}}</ref>

=== In popular culture ===
A running gag in ''[[Scott Pilgrim vs. the World]]'' features character [[Julie Powers]] being censored with the sound effects of the ZX Spectrum. The director of the film, [[Edgar Wright]], who was a big fan of the Spectrum, stated that he always used to wait for Spectrum games to load when he was a teenager.<ref>{{Cite magazine |last=Spitznagel |first=Eric |date=2010-08-12 |title=Scott Pilgrim Director Edgar Wright Sees No Difference Between Video Games and Heroin |url=https://www.vanityfair.com/culture/2010/08/scott-pilgrim-director-edgar-wright-sees-no-difference-between-video-games-and-heroin |access-date=2024-09-01 |magazine=Vanity Fair |language=en-US}}</ref> 

On 23 April 2012, a [[Google doodle]] honoured the 30th anniversary of the Spectrum. As it coincided with [[St George's Day]], the Google logo was of [[Saint George and the Dragon|St George fighting a dragon]] in the style of a Spectrum loading screen.<ref name="St. George's Day">{{cite web|title=St. George's Day / The 30th Anniversary of the ZX Spectrum|url=https://doodles.google/doodle/st-georges-day-the-30th-anniversary-of-the-zx-spectrum/|access-date=8 May 2012|url-status=live|archive-url=https://web.archive.org/web/20120507223012/http://www.google.com/doodles/st-georges-day-the-30th-anniversary-of-the-zx-spectrum|archive-date=7 May 2012}}</ref> 

One of the alternate endings in the [[interactive film]] ''[[Black Mirror: Bandersnatch]]'' (2018) included the main character playing data tape audio that, when loaded into a ZX Spectrum software emulator, generates a [[QR code]] leading to a website with a playable version of the "Nohzdyve" game featured in the film.<ref name="Bandersnatch">{{Cite web|url=https://www.avclub.com/bandersnatchs-stockpile-of-black-mirror-easter-eggs-inc-1831365758|title=Bandersnatch's stockpile of Black Mirror easter eggs includes a playable video game take on an old episode|last=Hughes|first=William|website=[[The A.V. Club]]|date=28 December 2018 |publisher=[[G/O Media]]|location=New York City|archive-url=https://web.archive.org/web/20231011181122/https://www.avclub.com/bandersnatchs-stockpile-of-black-mirror-easter-eggs-inc-1831365758|archive-date=11 October 2023|url-status=live|access-date=28 December 2018}}</ref>

== See also ==
{{portal|Video games|1980s|United Kingdom}}

* [[List of computer system emulators#Sinclair ZX Spectrum and clones]]
* [[List of ZX Spectrum games]]
* [[ZX Spectrum graphic modes]]
* [[ZX Spectrum character set]]
* [[Contended memory]]

== References ==
{{reflist}}

=== Sources ===
{{div col|colwidth=35em}}
{{refbegin}}
*{{cite journal |last1=Adams |first1=Stephen |title=Taking the lid off the Spectrum |journal=[[Sinclair User]] |date=July 1982 |issue=4 |url=https://archive.org/details/sinclair-user-magazine-004/page/n13/mode/2up?q=spectrum |access-date=3 October 2023 |publisher=[[EMAP]] |location=London }}
*{{cite book| title = Sinclair and the Sunrise Technology| last1 = Adamson | first1 = Ian| last2 = Kennedy | first2 = Richard| year = 1986| publisher = [[Penguin Books]] | location = [[Harmondsworth]], England|isbn = 978-0-14-008774-1}}
*{{cite journal|last1=Backhurst|first1=Nigel|title=Big response to call back|journal=Home Computing Weekly|issue=2|publisher=Argus Specialist Publications|location=London|date=15 March 1983a|url=https://archive.org/details/home-computing-weekly-002/page/n3/mode/2up}}
*{{cite journal|last1=Backhurst|first1=Nigel|title=Spectrums 'to double'|journal=Home Computing Weekly|issue=10|publisher=Argus Specialist Publications|location=London|date=10 May 1983b|url=https://archive.org/details/home-computing-weekly-010/page/n13/mode/2up}}
*{{cite journal|last1=Bourne|first1=Chris|title=Sinclair declares Spectrum price war|journal=[[Sinclair User]]|publisher=[[EMAP]]|location=London|issue=36|date=March 1985|url=https://archive.org/details/sinclair-user-magazine-036/page/n5/mode/2up|ref={{harvid|Bourne|1985a}}}}
*{{cite journal|last1=Bourne|first1=Chris|title=Sinclair declares Spectrum price war|journal=[[Sinclair User]]|publisher=[[EMAP]]|location=London|issue=44|date=November 1985|url=https://archive.org/details/Sinclair_User_044/page/4/mode/2up|ref={{harvid|Bourne|1985b}}}}
*{{cite journal |last1=Bradbeer |first1=Robin |title=Early promise is shown by colourful Spectrum |journal=[[Sinclair User]] |date=June 1982 |issue=3 |url=https://archive.org/details/sinclair-user-magazine-003/page/n13/mode/2up?q=spectrum |publisher=[[EMAP]] |location=London }}
*{{cite magazine |last1=Bradbeer |first1=Robin |title=Timex upgrades Spectrum |publisher=[[EMAP]] |location=London |url=https://archive.org/stream/sinclair-user-magazine-012/SinclairUser_012_Mar_1983#page/n81/mode/2up |via=[[Internet Archive]] |date=March 1983 |access-date=3 October 2023 |magazine=[[Sinclair User]] |volume=12 }}
*{{cite journal |last1=Clark |first1=Nigel |title=Sinclair User Magazine Issue 003 |journal=[[Sinclair User]] |date=June 1982 |issue=3 |url=https://archive.org/details/sinclair-user-magazine-003/page/n3/mode/2up?q=spectrum |access-date=3 October 2023 |publisher=[[EMAP]] |location=London }}
*{{cite journal |last1=Clarke |first1=Robin |title=Microcomputers: No room at the inn |journal=[[New Scientist]] |date=11 February 1982 |volume=93 |issue=1292 |location=London |language=en }}
*{{cite book|last=Dale |first=Rodney |year=1985 |title=The Sinclair Story |location=London |publisher=Duckworth |isbn=0-7156-1901-2}}
*{{cite journal |last1=Denham |first1=Sue |title=The complete quantum leap benchtest |journal=[[Your Spectrum]] |date=March 1984 |issue=2 |url=https://archive.org/details/ql-user/QL%20User%201984-01/page/n5/mode/2up |publisher=[[Future plc]] |location=[[Bath, Somerset|Bath]] |ref={{harvid|Denham|1984a}} }}
*{{cite journal |last1=Denham |first1=Sue |title=The secret that was Spectrum+ |journal=[[Your Spectrum]] |date=December 1984 |issue=10 |url=https://archive.org/details/your-spectrum-magazine-10/page/n105/mode/2up |publisher=[[Future plc]] |location=[[Bath, Somerset|Bath]] |ref={{harvid|Denham|1984b}} }}
*{{cite news| title = Sinclair's tinkering talent| author = <!-- not stated -->| newspaper = Engineering Today|location=London| pages = 20–23| date = 22 February 1982|ref={{harvid|Engineering Today|1982|pp=20–23}}}}
*{{cite journal|last1=Gore|first1=Brendan|title=The Engineer Behind The Spectrum|date=July 1982|journal=[[Your Computer (British magazine)|Your Computer]]|location=London|url=https://archive.org/details/your-computer-magazine-1982-07/page/n37/mode/2up}}
*{{cite news|title=The rise and fall of a British electronics wizard|last=Fraser|first=John|work=The Globe and Mail|location=[[Toronto]]|date=9 April 1986}}
*{{Cite journal |last1= Frey |first1= Franco |date= November 1985 |title= Kept in the dark |journal= [[Crash (magazine)|Crash]] |publisher= [[Newsfield Publications Ltd]] |location= [[Ludlow]] |issue= 22 |url= https://archive.org/details/Crash_Magazine_026/page/12/mode/2up }}
*{{Cite journal |last1= Frey |first1= Franco |date= March 1986 |title= Launch of the 128 |journal= [[Crash (magazine)|Crash]] |publisher= [[Newsfield Publications Ltd]] |location= [[Ludlow]] |issue= 26 |url= https://archive.org/details/crash-magazine-22/page/n5/mode/2up }}
*{{Cite journal |last1=Gilbert |first1=John |date=June 1983 |title=Spectrum prices are slashed |journal=[[Sinclair User]] |publisher=[[EMAP]] |location=London |issue=15 |url=https://archive.org/details/sinclair-user-magazine-015/page/n11/mode/2up |ref={{harvid|Gilbert|1983a}} }}
*{{cite journal |last1=Gilbert |first1=John |title=Programs program |journal=[[Sinclair User]] |date=July 1983 |issue=16 |url=https://archive.org/details/Sinclair_User_016/page/14/mode/2up?q=radio |publisher=[[Future plc]] |location=[[Bath, Somerset|Bath]] |ref={{harvid|Gilbert|1983b}} }}
*{{cite magazine |last1=Hartnell |first1=Tim |title=Review: Sinclair ZX Spectrum |date=June 1982 |magazine=[[Your Computer (British magazine)|Your Computer]] |pages=20–22 |volume=2 |issue=6 |publisher=[[IPC Business Press|IPC Business Press Ltd]] |location=London |url=https://archive.org/details/your-computer-magazine-1982-06/page/n19/mode/2up}}
*{{cite magazine |last1=Hayes |first1=Brian |title=The first personal computer for under $200 |magazine=Byte Magazine |date=January 1981 |volume=6 |issue=1 |url=https://archive.org/details/byte-magazine-1981-01/1981_01_BYTE_06-01_Hand-held_Computers?view=theater#page/n119/mode/2up |access-date=1 October 2023 |publisher=Byte Publications |location=[[New Hampshire]] }}
*{{cite journal |last1=Hayman |first1=Martin |title=Interview with Clive Sinclair |journal=[[Practical Computing]] |date=July 1982 |volume=5 |issue=7 |publisher=[[IPC Media|IPC Magazines Ltd]] |location=[[Sutton, London|Sutton]], London}}
*{{Cite book|title=Video Games: A Report on the Supply of Video Games in the UK|publisher=[[Monopolies and Mergers Commission]] (MMC), [[His Majesty's Stationery Office]]|date=April 1995|isbn=978-0-10-127812-6|location=United Kingdom|chapter=Market size and market shares|ref={{harvid|His Majesty's Stationery Office|1995|pp=[https://i.imgur.com/CLYiKIp.jpg 66], [https://i.imgur.com/vR9vtPX.jpg 68]}}}}
*{{cite journal|last=Hunt|first=Stuart|journal=[[Retro Gamer]]|publisher=[[Future plc]]|location=[[Bath, Somerset|Bath]]|issue=73|date=February 2010|title=The Ultimate Hero: A Complete History of Sabreman|url=https://archive.org/stream/retro_gamer/RetroGamer_073#page/n21/mode/2up|issn=1742-3155|oclc=489477015}}
*{{cite journal |last1=Johnston |first1=Mike |title=Spectrum excuses run out |journal=[[Sinclair User]] |date=October 1982 |issue=7 |url=https://archive.org/details/sinclair-user-magazine-007/page/n3/mode/2up?q=spectrum |access-date=3 October 2023 |publisher=[[EMAP]] |location=London }}
*{{cite journal |last1=Kean |first1=Roger |title=The Sinclair Story: Part Two |journal=[[Crash (magazine)|Crash]] |date=May 1985 |issue=16 |url=https://archive.org/details/crash-magazine-16/page/n125/mode/2up |access-date=9 October 2023 |publisher=[[Newsfield Publications Ltd]] |location=[[Ludlow]] |ref={{harvid|Kean|1985b}} }}
*{{cite journal |last1=Kelly|first1=David|title=Soft Soap from Sinclair |journal=[[Popular Computing Weekly]]|publisher=[[Future plc]]|location=[[Bath, Somerset|Bath]] |date=29 July 1982}}
*{{cite journal |last1=Kidd |first1=Graham |date=May 1986 |title=Amstrad has bought Sinclair Research |journal=[[CRASH (magazine)|CRASH]] |publisher=[[Future plc]] |location=[[Bath, Somerset|Bath]] |issue=28 |url=https://www.crashonline.org.uk/28/editrl.htm |access-date=23 October 2023 |archive-date=11 November 2023 |archive-url=https://web.archive.org/web/20231111201500/https://www.crashonline.org.uk/28/editrl.htm |url-status=live }}
*{{cite journal |last1=Laurie |first1=Peter |title=ZX80 Line-Up |journal=Practical Computing |date=April 1981 |volume=4 |issue=4 |url=https://archive.org/details/PracticalComputing1981April04/mode/2up |publisher=IPC Electrical Press Ltd |location=[[Sutton, Surrey|Sutton]] }}
*{{cite book |last1=Penix-Tadsen |first1=Phillip |title=Video Games and the Global South |date=2019 |publisher=Lulu |location=New York City |isbn=978-0-359-64139-0 |url=https://books.google.com/books?id=8PDCDwAAQBAJ |language=en |access-date=15 May 2024 |archive-date=16 May 2024 |archive-url=https://web.archive.org/web/20240516004122/https://books.google.co.uk/books/about/Video_Games_and_the_Global_South.html?id=8PDCDwAAQBAJ&redir_esc=y |url-status=live }}
*{{cite journal |title=Spectrum sales top 200,000 |journal=[[Popular Computing Weekly]] |date=17 February 1983 |volume=2 |issue=7 |url=https://archive.org/details/popular-computing-weekly-1983-02-17 |publisher=[[Future plc]] |location=[[Bath, Somerset|Bath]] |ref={{harvid|Popular Computing Weekly|1983a|p=1}} }}
*{{cite journal |title=Urgent recall notice |journal=[[Popular Computing Weekly]] |date=3 March 1983 |volume=2 |issue=9 |url=https://archive.org/details/popular-computing-weekly-1983-03-03/page/n5/mode/2up |publisher=[[Future plc]] |location=[[Bath, Somerset|Bath]] |ref={{harvid|Popular Computing Weekly|1983b|p=5}} }}
*{{cite journal |title=Spectrum tops 1/2 million mark |journal=[[Popular Computing Weekly]] |date=4 August 1983 |volume=2 |issue=31 |url=https://archive.org/details/popular-computing-weekly-1983-08-04 |publisher=[[Future plc]] |location=[[Bath, Somerset|Bath]] |ref={{harvid|Popular Computing Weekly|1983c|p=1}} }}
*{{cite journal|title=1m Spectrums|journal=[[Popular Computing Weekly]]|date=22 December 1983|volume=2|issue=51|url=https://archive.org/details/popular-computing-weekly-1983-12-22/page/n3/mode/2up|publisher=[[Future plc]]|location=[[Bath, Somerset|Bath]]|ref={{harvid|Popular Computing Weekly|1983d|p=5}}}}
*{{cite journal |last1=Pratt |first1=Terry |title=Sinclair's new baby |journal=[[Computer and Video Games]] |date=June 1982 |issue=8 |url=https://archive.org/details/cvg-magazine-008/page/n3/mode/2up?q=spectrum |publisher=[[Future plc]] |location=[[Bath, Somerset|Bath]] |ref={{harvid|Pratt|1982a}} }}
*{{cite journal |last1=Pratt |first1=Terry |title=Z-Extra: Spectrum anlaysis |journal=[[Computer and Video Games]] |date=July 1982 |issue=9 |url=https://archive.org/details/cvg-magazine-009/page/n93/mode/2up?q=spectrum |publisher=[[Future plc]] |location=[[Bath, Somerset|Bath]] |ref={{harvid|Pratt|1982b}} }}
*{{cite magazine|last1=Mott|first1=Tony|title=Videogaming: The Odyssey|magazine=[[Edge (magazine)|Edge]]|publisher=[[Future plc]]|location=[[Bath, Somerset|Bath]]|issue=80|date=January 2000|url=https://archive.org/details/EDGE.N080.2000.01/page/76/mode/2up}}{{dead link|date=September 2021 }}
*{{cite journal|last1=Munford|first1=Roger|url=https://archive.org/details/your-spectrum-magazine-07/page/n73/mode/2up|journal=[[Your Spectrum]]|publisher=[[Future plc]]|location=[[Bath, Somerset|Bath]]|issue=7|date=September 1984|title=Lunch with Sir Clive}}
*{{cite book| title = Effective scientific problem solving with small computers| last = Nash| first = John| year = 1984| publisher = Reston Pub. Co| location = [[Reston, Virginia|Reston]]| isbn = 978-0-8359-1596-0| url = https://archive.org/details/effectivescienti0000nash/page/216/mode/2up?q=timex+sinclair}}
*{{cite book |last1=Leigh |first1=Peter |title=The Nostalgia Nerd's Retro Tech |date=2018 |publisher=Ilex Press |location=London |isbn=978-1-78157-570-3}}
*{{cite book |last1=Leigh |first1=Peter |title=Nostalgia Nerd's Gadgets, Gizmos & Gimmicks: A Potted History of Personal Tech |date=2022 |publisher=Ilex Press |location=London |isbn=978-1-78157-889-6}}
*{{cite journal |last= Phillips |first= Max |date= November 1986 |title= ZX Spectrum +2 |journal= [[Your Sinclair]] |issue= 11 |url= https://archive.org/details/your-sinclair-11/page/n49/mode/2up |publisher= [[Future plc]] |location= [[Bath, Somerset|Bath]] }}
*{{cite journal |last1=Prata |first1=Fernando |title=TC 3256: A proposta Timex no mundo das aplicações profissionais |journal=Mircosete |date=13 May 1987 |issue=46}}
*{{cite journal |last1=Sawford |first1=Bruce |title=QL news |journal=[[Your Sinclair]] |date=July 1984 |issue=5 |url=https://archive.org/details/your-spectrum-magazine-05/page/n47/mode/2up?q=only+four+months+late |publisher=[[Future plc]] |location=[[Bath, Somerset|Bath]] }}
*{{cite journal | last1 = Scolding | first1 = Bill | date = May 1986 | title = Amstrad axes QL in Sinclair sell out | journal = [[Sinclair User]] | publisher = [[Future plc]] | location = [[Bath, Somerset|Bath]] | issue = 50 | pages = 7 | url = https://archive.org/details/sinclair-user-magazine-050/page/n5/mode/2up }}
*{{cite journal |last1=Segre |first1=Nicole |title=Sinclair profit is more than £14m |journal=[[Sinclair User]] |date=November 1983 |issue=20 |url=https://archive.org/details/sinclair-user-magazine-020/page/n17/mode/2up?q=spectrum |access-date=3 October 2023 |publisher=[[EMAP]] |location=London }}
*{{cite journal |last1=Shapiro |first1=Neil |title=Big bytes for little bucks |journal=[[Popular Mechanics]] |date=February 1984 |issue=2 |url=https://books.google.com/books?id=GuMDAAAAMBAJ&pg=PA98 |access-date=23 April 2024 |publisher=[[Hearst Communications]] |location=New York City |language=en |archive-date=16 May 2024 |archive-url=https://web.archive.org/web/20240516004133/https://books.google.com/books?id=GuMDAAAAMBAJ&pg=PA98#v=onepage&q&f=false |url-status=live }}
*{{cite journal |last1=South |first1=Phil |title=Watford plugs the gap |journal=[[Your Spectrum]] |date=November 1984 |issue=9 |url=https://archive.org/details/your-spectrum-magazine-09/page/n62/mode/1up?view=theater |publisher=[[Future plc]] |location=[[Bath, Somerset|Bath]] }}
*{{cite journal |last1=Tebbutt |first1=David |title=Benchtest: Sinclair ZX Spectrum |journal=[[Personal Computer World]] |date=June 1982 |volume=5 |issue=6 |url=https://archive.org/details/PersonalComputerWorld1982-06/page/118/mode/2up?q=spectrum |access-date=18 May 2024 |publisher=[[Incisive Media]] |location=London}}
*{{Cite journal |last=Wetherill |first=Steven |date=June 1984 |title=Tasword Two: The Word Processor |journal=[[Crash (magazine)|Crash]]|publisher=[[Future plc]]|location=[[Bath, Somerset|Bath]] |issue=5 |url=http://www.worldofspectrum.org/showmag.cgi?mag=Crash/Issue05/Pages/Crash0500126.jpg }}
*{{cite journal|last1=Williams|first1=Gregg|url=https://archive.org/stream/byte-magazine-1983-01/1983_01_BYTE_08-01_Looking_Ahead#page/n41/mode/2up|title=Microcomputer, British Style / The Fifth Personal Computer World Show|journal=[[Byte (magazine)|Byte]]|date=January 1983|publisher=[[UBM Technology Group]]|location=San Francisco}}
*{{cite book |last1=Wilkins |first1=Chris |title=The Story of the ZX Spectrum in Pixels: Volume 1 |date=2015 |publisher=Retro Fusion Books |location=[[Kenilworth]] |isbn=978-0-9931315-0-9|ref={{harvid|Wilkins|2015a}}}}
*{{cite book |last1=Wilkins |first1=Chris |title=The Story of the ZX Spectrum in Pixels: Volume 2 |date=2015 |publisher=Retro Fusion Books |location=[[Kenilworth]] |isbn=978-0-9931315-2-3|ref={{harvid|Wilkins|2015b}}}}
{{refend}}
{{div col end}}

== External links ==
{{Commons}}

* [https://www.worldofspectrum.org/ZXBasicManual/ ZX Spectrum] BASIC manual
* [https://jsspeccy.zxdemo.org/ JSSpeccy 3] ZX Spectrum emulator in the browser
* [https://worldofspectrum.org/ World Of Spectrum] ZX Spectrum Game Database
* [https://spectrumcomputing.co.uk/ Spectrum Computing] ZX Spectrum Database
{{Sinclair computers and clones}}
{{Amstrad}}

{{Authority control}}

[[Category:Computer-related introductions in 1982]]
[[Category:Computers designed in the United Kingdom]]
[[Category:English inventions]]
[[Category:Home computers]]<!-- Leave this, otherwise navigation is impossible for those who don't know what a Z80 is -->
[[Category:Products and services discontinued in 1992]]
[[Category:Sinclair Research]]
[[Category:Z80-based home computers]]
[[Category:ZX Spectrum]]