Normally an 801 router can share an ISDN S/T bus with an "ISDN modem" (better called a "TA") without any problem. I use an 803 at home on the same S/T bus as a AVM USB TA, without any problem.
The only problem you might run into is with incoming calls, if you only have one subscriber number on the ISDN line, and both devices are programmed to pick up incoming calls to that number. It will be pot-luck which one picks up the call first. I have four different subscriber numbers on my ISDN line, and I program a different number on each device on the S/T bus.
What is the "ISDN modem", and exactly what problems are you experiencing?
Kevin Dorrell
Luxembourg
