Connecting Bri Interfaces For Pstn Fallback; Figure 5-7: Pstn Fallback For Bri Ports - AudioCodes Mediant 600 Hardware Installation Manual

5.7

Connecting BRI Interfaces for PSTN Fallback

The PSTN Fallback feature provides a BRI interface connection to the PSTN upon a power
outage (i.e., Ethernet link failure). This allows a telephone or PBX connected to a BRI port
to continue making calls through the PSTN network (instead of through the IP network).
The PSTN Fallback is provided by connecting adjacent BRI ports, where one port is
connected to, for example, a PBX and its adjacent port is connected to an active PSTN line
(i.e., normal operation, not only dedicated to Fallback). In the event of a power failure, a
relay connects the adjacent BRI ports (i.e., ports I to II, and ports III to IIII) by the closing of
a metallic switch inside the module.
Notes:
Hardware Installation Manual

Figure 5-7: PSTN Fallback for BRI Ports

•
Damage can be caused to external equipment if PSTN Fallback is
activated on two ports that are configured as user side.
•
Ensure that paired BRI ports (i.e., ports I and II, and ports III and IIII) are
not identically configured (i.e., one must be user the other net side);
otherwise, PSTN Fallback does not function.
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Mediant 600
Document #: LTRT-85609