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FXO Port Issues On 2821 with Version 12.4(22)T RS and UCM 6.1


I have been facing a strange issue on my FXO Port which is being used to connect to POTS and then via a FXS connected to the Fax Machine.

Whenever someone dials the number from POTS, it works correctly for the first time i.e. establishes the connection to FXS and the fax machine rings and finally gets the fax delivered.

However if I were to disconnect the call after dialing and hearing 2 ring back tones and dial again, the call simply gets stuck at the FXO Port i.e. I hear the Fax Tone / Modem Handshake noise and nothing else happens.

I suspect its an issue with the time out as the FXO doesnt release the previous call and gets stuck even though when the second call comes in, it doesnt give a Busy Tone or Ring Back Tone.

I did the debug vpm signal and the output as attached.

Any help would be greatly appreciated.


Sam wilson