kevin@harvard.ARPA (Kevin Crowston) (05/30/85)
> If you wanted to make a DB9 to DB9 RS422 cable > then 1 straight through, and 5&9 swapped should do it. I tried this first and it didn't work (probablly due to software problems. I then looked at an Imagewriter cable and found that it connected: 9-pin Mac end 23-pin Imagewriter end 3 and 8 7 5 2 / these two might be swapped 9 3 \ 7 (something else) Questions: 1) Are macs 9-pin connector's pin 1 and 3 (both called ground) identical? 2) Why would pin 3 and 8 be shorted together (the Imagewriter does work, so it probablly isn't by accident)? Should my cable short these pins? 3) Do I need to hook mac 9-pin connector's pins 7 together? (Pin 7 was caled "incoming handshaking"; I guess it doesn't need to be hooked together, but might need to be grounded). Any help anyone can offer will be most appreciated. As I said before, I suspect the problems I'm having are mostly software, but I would like to be sure the cable is right. -- Kevin Crowston UUCP: {seismo,ut-sally}!harvard!kevin MIT Sloan School of Management ARPA: kevin@harvard.ARPA