Editing MIDI (section)

===Connectors and interface===

==== DIN connector ====
Per the original MIDI 1.0 standard, cables terminate in a [[DIN connector|180° five-pin DIN connector]] (DIN 41524). Typical applications use only three of the five conductors: a [[ground (electricity)|ground]] wire (pin 2), and a [[balanced pair]] of conductors (pins 4 and 5) that carry the MIDI signal as an [[electric current]].<ref>{{cite web|title=5 Pin DIN Electrical Specs|url=https://www.midi.org/specifications/midi-transports-specifications/5-pin-din-electrical-specs|access-date=2021-04-08|website=The MIDI Association|language=en-gb|archive-date=28 May 2021|archive-url=https://web.archive.org/web/20210528115750/https://www.midi.org/specifications/midi-transports-specifications/5-pin-din-electrical-specs|url-status=dead}}</ref><ref name="Bozeman">Bozeman, William C. ''Educational Technology: Best Practices from America's Schools''. Larchmont: Eye on Education, 1999.</ref>{{rp|41|date=November 2012}} This connector configuration can only carry messages in one direction, so a second cable is necessary for two-way communication.<ref name="Huber 1991">{{cite book |last=Huber |first=David Miles |title=The MIDI Manual |location=Carmel, Indiana |publisher=SAMS |date=1991 |isbn=978-0-672-22757-8 |url=https://archive.org/details/midimanual00hube }}</ref>{{rp|13|date=November 2012}} Some proprietary applications, such as [[Phantom power|phantom-powered]] footswitch controllers, use the spare pins for [[direct current]] (DC) power transmission.<ref>Lockwood, Dave. "[http://www.soundonsound.com/sos/dec01/articles/tcgmajor.asp TC Electronic G Major] {{webarchive|url=https://web.archive.org/web/20120320113908/http://www.soundonsound.com/sos/dec01/articles/tcgmajor.asp |date=20 March 2012 }}". ''Sound on Sound''. SOS Publications. Dec 2001. Print.</ref>

[[Opto-isolator]]s keep MIDI devices electrically separated from their MIDI connections, which prevents [[Ground loop (electricity)|ground loops]]<ref>Mornington-West, Allen. "Digital Theory". ''Sound Recording Practice''. 4th Ed. Ed. John Borwick. Oxford: Oxford University Press, 1996.</ref>{{rp|63|date=November 2012}} and protects equipment from voltage spikes.<ref name="Manning3" />{{rp|277|date=November 2012}} There is no [[error detection]] capability in MIDI, so the maximum cable length is set at {{convert|15|meters|feet}} to limit [[interference (communication)|interference]].<ref>"[http://www.richmondsounddesign.com/faq.html#midilen Richmond Sound Design&nbsp;– Frequently Asked Questions] {{webarchive|url=https://web.archive.org/web/20060105205625/http://www.richmondsounddesign.com/faq.html |date=5 January 2006 }}". ''richmondsounddesign.com''. Web. 5 August 2012.</ref>

==== TRS minijack connector ====
To save space, some MIDI devices (smaller ones in particular) started using 3.5&nbsp;mm [[Phone connector (audio)|TRS phone connectors]] (also known as audio minijack connectors).<ref>{{cite web |last=Kirn |first=Peter |date=2015-08-26 |title=What if we used stereo minijack cables for MIDI? |url=https://cdm.link/2015/08/used-stereo-minijack-cables-midi/ |url-status=live |archive-url=https://web.archive.org/web/20230419015513/https://cdm.link/2015/08/used-stereo-minijack-cables-midi/ |archive-date=2023-04-19}}</ref> This became widespread enough that the MIDI Manufacturers' Association standardized the wiring.<ref>{{cite web |title=Specification for TRS Adapters Adopted and Released |url=https://www.midi.org/midi-articles/trs-specification-adopted-and-released |website=www.midi.org |access-date=30 August 2023 |archive-date=30 August 2023 |archive-url=https://web.archive.org/web/20230830172520/https://www.midi.org/midi-articles/trs-specification-adopted-and-released |url-status=dead }}</ref> The MIDI-over-minijack standards document also recommends the use of 2.5&nbsp;mm connectors over 3.5&nbsp;mm ones to avoid confusion with audio connectors.<ref>{{cite web |date=21 August 2018 |title=It's official: minijack connections are now kosher for MIDI |url=https://cdm.link/2018/08/midi-minijack-trs/ |access-date=24 July 2019 |archive-date=24 July 2019 |archive-url=https://web.archive.org/web/20190724033640/https://cdm.link/2018/08/midi-minijack-trs/ |url-status=live }}</ref>