I am working with alarm signalling systems at the moment, and they communicate with 2400bps v22bis modems.
I would like to be able to intercept the traffic on the phone line as a proof of concept.
The only device/software I can find to do this is the 3am Linescope.
This appears to be a phone line to audio adapter, connected to a sound card with some software. It is ~€500 so is quite costly.
As far as I understand it, technically intercepting v22bis traffic is possible, it just looks like it is not a common task.
Does anyone know of any cheaper or free alternatives?