len@qumix.UUCP (Leonard Labar) (09/30/84)
I own a vicmodem for my commodore vic20 and recently bought a macintosh. The mac has a RS422 modem port. Has anyone tried making a cable to convert the vicmodem to RS422 or RS432? I realize this is really off the wall but I think there is a chance to make this work. I just don't want to be the first on the block and damage something. Also, has anyone tried tackling the software/hardware interface to make a commodore 1525 printer work with the Mac? I know some limited conversions have been done with qume and epson and others.
len@qumix.UUCP (Leonard Labar) (10/05/84)
This is what I have on paper so far. Anyone tried something like this yet? -----RS422 (+5v line driver/receiver)----- MAC function breadboard VICMODEM function 1,3 ground ground 1,12,A,N ground 2 +5v pwr to ic ------ 4 TXD+ --> 3.3k pullup --> M data to modem 5 TXD- ---- ---- 6 filtered +12v ---- 10 modem power 7 carrier detect<- LS04-8, 6 to 9, 5 to H,K carrier detect 8 RXD+ ---- ---- 9 RXD- <-- LS04-4 &1k res., 3 to <- B,C data from modem back of mac ------------- \5 4 3 2 1 / \9 8 7 6 / -------- The Macintosh book (red cover) seems to say you can run the RS422 lines open ended like this. They talk about doing it with the imagewriter. I have yet to hook this up and try it. Also, I want to make sure the "back of mac" shows the pinouts in the right place.