Connecting 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 if the device houses one or more BRI modules, where each BRI module provides 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) of the 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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BRI port cabling must be routed only indoors and must not exit the building. |
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To protect against electrical shock and fire, use a 26 AWG min wire to connect the BRI ports to the PSTN. |
Cable specifications:
RJ-45 Connector Pinouts for BRI PSTN Fallback
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➢
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To connect the BRI line interfaces for 1+1 PSTN Fallback: |
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1.
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Connect line 1 to a PBX. |
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2.
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On the same BRI module, connect line 2 to the PSTN. |
Cabling (Ports 1 and 2) PSTN Fallback
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PSTN Fallback is supported only on BRI interfaces. |
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PSTN Fallback is supported only between ports on the same BRI module. |
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This PSTN Fallback feature has no relation to the PSTN Fallback Software Upgrade Key. |