Protocol analyser or spy software ?
Those links you show are interesting ...
I thought a protocol analyser just showed the comms format as per
https://www.tti-test.com/products-tti/text-pages/la-da100.htm
I have got the DA100 with breakout box and LCD display but don't really trust it, it is better than nothing for 'cracking' an RS232 link but occasionally (maybe 20%) gets it wrong :cry:
Your links seem to show something closer to evesdropping software - not trying to find data rate, parity and number of stop bits as the actual data being sent ???
I appreciate these are connecting to the telephone line side of a modem but I'm still surprised by the name 'protocol analyser' - I guess you never stop learning :!:
As far as the modem comms is concerned - how much variation are you expecting in data rate, tone specification, data encryption ????
If this is little more than a third modem pre-configured to a known set-up feeding into a 'termonal' program then it would be easy to do.
If you need to automatically configure the modem to an unknown spec. then that could be a real challenge
I have had some success writing Visual Basic 'spy' software but this assumes the data format is already understood and just needs translation.
Can you give us more info on the application ? or is this purely a 'notional project' ?