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ISDN PRI w/ FXO Failover

Can the TA900 Series w/ FXO be used as failover for the ISDN PRI interface? We currently use a similar configuration w/ SIP Proxy but was wondering if the same applies for a traditional ISDN PRI interface. IE: We deliver SIP trunks to the Adtran then hand-off IDSN PRI to the customer. If the WAN connection goes down (SIP trunks) we want "at least" outbound emergency dialing and possibly a backdoor inbound route for incoming calls to the specific FXO number.

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Honored Contributor
Honored Contributor

Re: ISDN PRI w/ FXO Failover

Yes. For outbound, configure the FXO voice grouped-trunk with the same patterns as the PRI but a higher cost.

For inbound, do the following:

On your FXO trunk add the line:

trunk-number 3015550110

where "3015550110" is the extension on the PBX of your auto-attendant or whatever destination you want FXO callers to reach. This should be whatever digit length you have in the accept pattern of the PBX's voice grouped-trunk. Ten digits for example here.

Note that inbound calls that ring the FXO will route to the PBX all the time, regardless of whether the PRI is up or down.