Editing ZX81 (section)

== Clones and variants ==
{{Main|List of ZX80 and ZX81 clones}}
[[File:Timex Sinclair 1000 FL.jpg|right|thumb|The Timex Sinclair 1000, a licensed ZX81 variant produced for the US market by Timex in 1982–83. It was initially highly successful but sales soon collapsed.]]
[[File:Microdigital TK85 with joystick.JPG|right|thumb|The TK85, an unauthorised ZX81 clone produced by Microdigital Eletronica of Brazil]]
Sinclair's licensing agreement with Timex enabled the American company to produce three clones or offshoots of Sinclair machines for the US market. These were the [[Timex Sinclair 1000]], [[Timex Sinclair 1500]] (both variants of the ZX81) and the [[Timex Sinclair 2068]] (a variant of the ZX Spectrum). The TS1000 was launched in July 1982 and sparked a massive surge of interest; at one point, the Timex phoneline was receiving over 5,000 calls an hour, 50,000 a week, inquiring about the machine or about microcomputers in general.{{sfn|Adamson|Kennedy|1986|p=121}} It was virtually identical to the ZX81 save for re-branding and the addition of an extra 1&nbsp;KB of memory, totalling 2&nbsp;KB. In the five months following the TS1000's launch, the company sold 550,000 machines, earning Sinclair over $1.2&nbsp;million in royalties.{{sfn|Adamson|Kennedy|1986|p=134}}

Timex produced a second version of the ZX81 in the form of the TS1500, essentially an Americanised ZX81 launched in August 1983. It dispensed with the membrane keyboard and used a case similar to that of the ZX Spectrum, incorporating 16&nbsp;KB of on-board memory.{{sfn|Adamson|Kennedy|1986|p=140}} It was effectively a stopgap between the ZX81 and Spectrum. However, it was unsuccessful due to increased competition from rival US machines and the after-effects of Timex's botched marketing of the TS1000. Although the TS1000 had initially been a great success, Timex failed to provide the essential RAM pack upgrades to the market for two or three months after it launched the TS1000. Consumers would take the machine home, plug it in and find that it would not do anything useful due to the lack of memory.{{sfn|Adamson|Kennedy|1986|p=135}}

In addition, consumers' attitude in the US was quite different from that in the UK. Clive Sinclair told ''Informatics'' magazine in June 1981 that "our competitors thought that consumers didn't want to learn programming. We [Sinclair Research] think they failed because of this and because of price."{{sfn|Adamson|Kennedy|1986|p=135}} Timex evidently shared this belief but events proved it to be a false assumption. The TS1000/ZX81's price advantage was erased when its main rivals – the [[TI-99/4A]] and the [[VIC-20]] – had their prices cut to below the all-important $100 mark.{{sfn|Adamson|Kennedy|1986|p=137}} Competitors such as Apple, Atari, Commodore and Texas Instruments promoted their machines as being for business or entertainment rather than education, highlighting the value of computers with ready-made applications and more advanced features such as graphics, colour and sound.{{sfn|Adamson|Kennedy|1986|p=136}}

By late 1983 [[Wayne Green]] reported a "rising chorus of frustrated Timex users who are telling friends not to waste their money." "Hard core" [[early adopters]], he wrote, "became discouraged with the quality of the product, with the poverty of software available and with the almost total lack of information on how to cope with it."<ref name="green198311">{{cite news |author=Green, Wayne |title=Hot Cider |work=inCider |page=6 |url=https://archive.org/stream/inCider_83-11#page/n5/mode/2up |via=[[Internet Archive]] |date=November 1983 |access-date=7 January 2015}}</ref> Consumers deserted the TS1000 once its novelty value had worn off and, as publishers of programming guides found to their cost, the American public showed little interest in using the machine to learn about computer programming. American retailers were left with large stocks of unsold machines. Burned by this experience, many were unwilling to stock the later Timex Sinclair machines in large numbers and the big chain stores dropped the Timex Sinclair line altogether.{{sfn|Adamson|Kennedy|1986|p=141}}

Some companies outside the US and UK produced their own "pirate" versions of the ZX81 and Timex Sinclair computers,<ref name="bradbeer198303">{{cite news |author=Bradbeer, Robin |title=Timex upgrades Spectrum |work=Sinclair User |pages=83–84 |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=28 January 2015}}</ref> aided by weak intellectual property laws in their countries of origin. Several Brazilian companies produced ZX81 clones, notably the TK series (such as the [[TK85]]) from [[Microdigital Eletronica]] of Brazil)<ref>[[#MCI-TK85|Museu da Computação e Informática]]</ref> and [[Prológica Indústria e Comércio de Microcomputadores|Prológica]]'s [[CP-200]]. [[Czerweny computers|Czerweny Electrónica]] of Argentina produced the CZ1000 and CZ1500, clones of the ZX81 and TS1500 respectively. Lambda Electronics of Hong Kong produced the [[Lambda 8300]], based on the ZX81, which was itself widely copied by other Chinese manufacturers.<ref>{{cite news |title=Send in the clones |work=AlchNews |issue=33 |publisher=Alchemist Research |year=2000 |url=http://www.worldofspectrum.org/infoseekid.cgi?id=0013980}}</ref>

The machines were not all straight copies of the ZX81; some, such as the CP-200, came with extra memory and a larger case (often with a [[chiclet keyboard]] in place of the original membrane keyboard). One clone, the TL801 from TELLAB of Italy, could emulate either the ZX80 or ZX81 and switch between the two machines via a jumper.