Re: HP41 - RS232 - PC Interfacing Message #4 Posted by Garth Wilson on 6 Jan 2006, 1:21 p.m., in response to message #3 by Christoph Klug
Standard pin usage is as follows:
9-pin desc dir 25-pin
1 (DCD) I 8
2 RD 1 3
3 TD O 2
4 DTR O 20
5 GND 7
6 DSR I 6
7 RTS O 4
8 CTS I 5
9 (RI) I 22
The "I" and "O" above for "input" and "output" refer to what's connected to the DB-9 end. The DCD and RI are only used for modems, which you're not dealing with right now. All the DB-25 pins are defined except for 9, 10, 18, and 25 which are reserved, but it's rare to see more than the "big 8" actually used. Those are the ones shown above, minus RI. The FSI164A HPIL-RS232 interface converter used the extra pins for more channels. I just got the standard model, so I only have two channels; but there was the option to go up to 8, and they all went through the DB-25. The extra channels only had TD & RD, no handshaking lines.
|