On May 20, 1986 the ZMODEM protocol specification posted to Usenet. For more info on zmodem and Chuck Forsberg of Omen Technology visit:

Usenet post: [https://www.tuhs.org/Usenet/comp.sources.unix/1986-May/004372.html]

About Zmodem:
[https://grokipedia.com/page/ZMODEM]

https://www.tuhs.org/Usenet/comp.sources.unix/1986-May/004372.html