Two Programs / One Modem

Posted on 2003-11-10
Last Modified: 2010-05-01
I have the need for a program to monitor a modem that is controlled by another program. How can I do this?

Long long ago I was able to do this on an Amiga but I don't know how (or if it can even be done) on a PC using VB6.

I basically want to open the modem in a listen only mode and then let another program open the same modem at the same time for full control.
Question by:schworak
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Expert Comment

ID: 9716632
I think a possible solution would be to create a small software layer that respond to a virtual COM port you create.
Then from this COM port you open the actual Port.

The application should always ask to your virtual COM in order to access the real one.

It is a kind of COM Proxy.

I wrote something like this almost 10 yeas ago.

If I manage to remember or find something I'll let you know.

Try to look here:

Hope this helps,


Author Comment

ID: 9719786
Hmmm, that link doesn't work. I will try to find some info on virtual COM port.

Accepted Solution

MaxPol earned 250 total points
ID: 9721088
If you want I can send you the doc.

Let me know.


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Author Comment

ID: 9723093
That would be great.

Author Comment

ID: 9752798
The ACOMPORT active X control gives control over the port but doesn't help in this situation.

Author Comment

ID: 9754441
The information you provided was good. It didn't address my situation but I am thinking that it may not be possible to do what I am after. Basically, I want to intercept all the data coming from the modem but not interact with the modem in any way. I have a commercial program that sits on the modem and controls it but I wanted to listen in to see the incoming traffic and record some events.

It just doesn't look like it is possible but thanks for the help anyway.

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