We are looking for ready-made telephone modules that can connect to an ISDN or IP-telephone PBX. They should have some sort of control interface (typically UART) for dialing, hang-up, ring, etc., and analogue audio in and out.
/Long/ ago, I used an analogue modem module like this. I also had an ISDN modem module, but it didn't support audio in and out - it was only for data. And of course they are now out of production anyway.
Ideally we would like one supplier that can provide both kinds of modules, so that we can easily swap them out depending on which version the end-user needs. But at the moment, we are interested anything we can find.
Our customer has a very short schedule here, so we want to find something ready-made - and I'd like to avoid learning about IP telephony if I can!
mvh.,
David