User`s manual

MediaPack BRI Series
User's Manual 36 Document #: LTRT-83702
3.4.6 Connecting the PSTN Fallback Port
The Fallback feature uses identical cabling as the normal ports. The PSTN fallback port
allocation depends on the MediaPack model:
 MP-404 /BRI /ST /AC /FB: ports 0 and 1 are interconnected if the gateway is not
powered
 MP-408 /BRI /ST /AC /FB: ports 0 and 1, and ports 2 and 3 are interconnected if the
gateway is not powered
Figure 3-12: Fallback Cabling (MP-404 /BRI /ST /AC /FB and MP-408 /BRI /ST /AC /FB)
Warning: If Fallback is activated on two ports that are configured as user side,
damage can be caused to external equipment. Ports 2 and 0 must be
configured as Point to Point, User side interfaces. For additional
information on configuring the ISDN ports, refer to Chapter 6.
Notes:
• If ports 0 and 1, and ports 2 and 3 are configured identically (both user
and both net side), Fallback does not function.
• If ports 0 and 1, or ports 2 and 3 are configured as user side (i.e.,
connected to systems that provide power), Fallback does not function
and the external equipment can be damaged.
• The MediaPack is protected against such invalid configurations as
described above.