dbo@cosivax.UUCP (07/24/84)
The modem signals as published in ST.mac (May 1984) are as follows: MAC APPLE MODEM 1. frame ground nc 2. +5v data set ready 3. signal ground signal ground 4. transmit data + not connected 5. transmit data - receive data 6. +12v data terminal ready 7. input (HSC) carrier detect 8. receive data + frame ground 9. receive data - transmit data The connections they suggest are: 3. <-> 3. 5. -> 9. 6. -> 6. 7. <- 7. 9. <- 5. I have had success connecting my U.S. Robotics modem using the following scheme: MAC (db9) ROBOTICS (db25) 3. -> 7. (signal ground) 5. -> 2. (transmit data) 7. <- 8. (carrier detect) 9. <- 3. (receive data) I didn't bother to run a high signal from MAC 6. to data terminal ready (ROBOTICS 20) because the modem doesn't seem to need it and I don't really care if the modem hangs up when I turn my terminal off (also, I had some 4 wire cable handy, so it was just more convenient). This setup works fine for a Mac running MacTerminal.