I'll start it off...
Back in the very early 1990's (a few years before the Internet came onto the scene) there was a Zmodem program being developed for the TI by a guy by the name of Gary Bowzer.
The Zmodem protocol would have given us the ability to call more varied systems, but it appears now from 2016 it did not catch on.
My questions are:
1) What ever happened to this protocol for the TI?
2) Was this just a stand alone program? I ask because I've never seen the Zmodem protocol incorporated in any other program.
3) Did it die because Xmodem was 'good enough' for TI'ers?
4) Did it die from lack of interest (few BBS users and fewer downloaders)?
I don't recall Gary working on Zmodem.
Jeff Brown was working on Zmodem though I don't know how far he was able to implement.
I gave up on Zmodem during my efforts to create a Fidonet mail daemon. Compression and other 'requirements' became too complicated to implement and the methods changed too often. The stubs were eventually removed from my BBS software. Also, for the TI at that time, Zmodem didn't provide much beyond the other multiple file transfer protocols including Mass Transfer's X and Y modem operations, standard Ymodem, and Ymodem-g. I have actually entertained removing some protocols from TIMXT, PORT, and S&T BBS for sake of simplicity in the current 'world'.