Connecting PSTN Fallback for E1/T1 Trunks
The device supports PSTN Fallback for E1/T1 lines. If the device loses power, for example, due to a power outage or the unplugging of its power cable, it automatically routes calls that are received from the Tel side (e.g., PBX) directly to the PSTN (instead of to the IP network).
Support for PSTN fallback:
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Mediant 800B: PSTN Fallback is supported only when using a module with dual E1/T1 ports. In the event of a PSTN fallback, the module's metallic relay switch automatically connects Port #1 with Port #2 to route calls between the Tel and PSTN side. |
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Mediant 800C: In the event of a PSTN fallback, the module's metallic relay switch automatically connects Port #1 with Port #2 (and Port #3 with Port #4 for the four E1/T1 port module) to route calls between the Tel and PSTN side. These ports must be on the same module. |
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PRI 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 PRI ports to the PSTN. |
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To comply with EMC rules and regulations, use shielded twisted pair (STP) cables for E1 interfaces. |
Cable specifications:
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Cable: STP cable of 26 AWG min. |
RJ-48c Connector Pinouts for E1/T1 PSTN Fallback
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To connect the PRI ports for PSTN Fallback: |
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Connect one of the PRI ports to the PBX. |
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Connect the second PRI port to the PSTN. |
Cabling PRI Ports for PSTN Fallback
It doesn't matter which PRI port you use to connect to a Tel entity (i.e., PBX or PSTN).