Listen to RS232

Posted on 2008-11-09
Medium Priority
Last Modified: 2013-11-23
Hello Experts.
I have a Program that is running and writting to the RS232 Comm Port. I do not have the source to that program.
I need a program - running on the same machine - that can 'Listen' to the Comm Port.
Can you please assist me ?
Question by:HESUS
  • 2

Expert Comment

ID: 22919587
I know where you're comming from, I was in the exact same situation a while ago.
I used the free edition of the following listener: http://www.serial-port-monitor.com/

Author Comment

ID: 22920512
Thanks, but I need myown code so I can use the data I read, for another application.

Accepted Solution

huferry earned 200 total points
ID: 22937579
Normally you'll need a machine with 2 com ports and a cross cable. The writting program can use COM1 and the listening program can use COM2. You have to cross the two hardware COM ports using a cross serial cable. Make sure that both programs are connected using the same baudrate, number of bits, etc.

An alternative, if you don't have hardware COM ports you can use a program that creates virtual COM ports and transfer the data using TCP/IP. I have use one of those:


You can run the program twice and sets,

Program 1, creates COM3 and acts as a TCP server that listen to port 9000.
Program 2, creates COM4 and connects to on port 9000 (it's important that you start the server first).

If you've done this you'll have COM3 and COM4 virtually and crossed each other.
Then you can start your applications which use the serial port and connect them to COM3 and COM4.

Author Comment

ID: 22937965
Thank you very much.
I am looking for an option to write the code myself, using Delphi or C. Then I can be much more flexible with the data, and make it as part of another program.

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