The Branch Gateway supports the following serial modems:
Multitech MultiModem ZBA, MT5634ZBA-V92.
Multitech BRI-NT1 ISDN Modem w/ POTS, MTA128NT, for use in US and Canada.
Multitech ISDN Modem w/ POTS, MTA128STBRI, for use in Europe and the rest of the world. The ISDN modems require DB-25 termination as well as the RJ-45 cable.