Identify program controlling rs232 port

On a box running Server 2003 the application needs to talk out a serial port to an OPTO-22 I/O system. The Optoscan program from the manufacturer works just fine. Our application (which has been used many times before successfully) is not sending or receiving message. It appears that another application has grabbed the port.

Does anyone know how to identify which program is controlling a serial port?

Thanks

 

Portmon is a utility that should be able to tell you the name of the process that is accessing the port: http://www.microsoft.com/technet/sysinternals/processesandthreads/portmon.mspx

I use it at work as a RS-232/RS-422 protocol analyzer.

 

Thanks. WIll give it a try.