Author: James T. Walker
Date: 20:08:49 11/28/98
Go up one level in this thread
On November 28, 1998 at 21:31:37, Robert Hyatt wrote: >On November 28, 1998 at 13:47:54, Christophe Theron wrote: > >>On November 27, 1998 at 19:04:14, James T. Walker wrote: >> >>>I'm trying to get my two computers to communicate via the serial ports with a >>>null modem cable. Both are running win98. I can't make it happen. I'm working >>>towards auto testing of chess programs. If anyone can help me through email I >>>would appreciate it. I don't want to tie up this site with a non chess thread. >>>Both computers act like they are working. The PII is set up as the "host" and >>>the AMD is set up as the "Client". The host is listening and the client is >>>communicating but they don't hear each other. I'm using a brand new null modem >>>cable which I checked out the connections on today. I'm lost ! >>>Please if you can help off line by email. >>>Thanks, >>>Jim Walker >> >>What software do you use to link the 2 computers together? >> >>If you use Auto232, I think that a null modem will not do the job. >> >>I think the Auto232 cable has been specially twisted somewhere to avoid the use >>of a standard null modem cable. A kind of copy protection I suppose. >> >> >> Christophe > > >There's not really any way you can do this. DB-9 to DB-9 is a hardware >issue and not a software issue. The ports *must* be tied together with a >null-modem cable, because you have to cross transmit and receive, and you >have to cross RTS and CTS for flow control... plus others like DCD, etc. > >first test would be to make two "hyper-terminals" talk to each other over >that connection. You should be able to direct both to the serial port, >make sure the baud rates are correct, of course. Then what you type on >one keyboard should echo on the other machine's terminal window. If this >works, you should be ready to communicate with anything across that cable. > >Until this works, forget auto232 testing. After reading your Post, I loaded the Hyper-terminal programs on both computers and tried to communicate with them. Still no communications even though one computer indicated it was connected and tried to send a text file. The text file showed up on the "senders" screen with an "error" preceeding every line. The receiver never indicated it received anything. Nothing on the keyboard shows up on the second computer. It looks like both computers are working but nothing is getting through. I checked the null modem cable for continuity. All pins are straight through connections except 2&3 are crossed. I think this is the norm for RS232. Does anybody out there know how to test the com ports to be sure they are working?? Jim Walker
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.