Is it possible to listen communication at serial port like fiddler or wireshark?

Question

I have a very old program which communicates COM1 port of my computer. The porgram sends command to a PBX box and receives the answer from box. Now I have to re-write the program (because it is too old and can't meet our needs) for new features we need. But the problem is we have no data-sheet or something else about how to communicate with box. So I decided to listen communication on COM1 port but how?

Answer 1

Actually it should be quite easy to do with a little bit of hardware, just tap the serial port wires.

http://www.stratusengineering.com/EZTap.html

http://www.lammertbies.nl/comm/cable/RS-232-spy-monitor.html

I suppose you are looking for something more like:

http://technet.microsoft.com/en-us/sysinternals/bb896644.aspx

but I don't know what platform you are on, so it is hard to make a recommendation. Whereas the hardware tap will work on any platform.

Answer 2

Advanced Serial Port Monitor -> Spy mode. http://www.aggsoft.com/serial-port-monitor.htm