ISDN
you can use a TA a/b or a small pabx which provides you with some a/b adapters.
There you can plug in your analog devices like modem, fax, etc. I have recently
bought such a thing in Germany for $400 US. You should be able to get it even
cheaper. Just make sure that you no NOT buy an ISDN card with a build-in
U-interface but with an extra NT (Network Terminator) which provides a
S0-Interface as a BUS. There you can plug in several ISDN devices and adress
them with different MSM (Mutiple Subscriber Numbers).
good luck
Peter Geier 100064,3667