Allan...
I read the info you posted for me. Thanks. However, I still am not convinced that I can just pick any modem and plug it in. Where the modem contacts are, I have noticed in looking to purchase one, that there are 2 obvious contact configurations. I really don't think that these different contact points will plug into the same socket. The modem I took out has a 2 section contact area, a long section with 49 contacts, then a slot and then a short section with 11 contacts.
Other modems I looked at have a 3 section contact area. I can't see how 2 different contact surfaces can be plugged into the same socket.
Unless I am missing something....