Connecting the PSTN Fallback for BRI Lines

The device supports PSTN Fallback for BRI lines. If the device loses power, for example, due to a power outage or the unplugging of its power cable, it automatically routes calls from the Tel side to the PSTN (instead of the IP network).

PSTN Fallback is supported only on BRI modules that provide two or four spans. In the event of a PSTN fallback, the BRI module's metallic relay switch automatically connects line Port 1 (I) to Port 2 (II), and / or line Port 3 (III) to Port 4 (IIII) of the same BRI module.

For example, if a PBX trunk is connected to Port 1 and the PSTN network is connected to Port 2, when PSTN Fallback is activated, calls from the PBX are routed directly to the PSTN through Port 2.

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To connect the BRI line interfaces for 1+1 PSTN Fallback:

1.

Connect line 1 to a PBX.

2.

On the same BRI module, connect line 2 to the PSTN.

Cabling (Ports 1 and 2) PSTN Fallback