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Please help-Ringback on PSTN


Sometime ago i deployed CCME for one of our clients,there is a 2801 router with 8 PSTN lines terminated on 8 FXO ports,which then goes to a number of POE switches.

This set-up has been working okay,the problem is that the receptionist reports the whenever someone calls from the PSTN he/she hears multiple rings on their end,but the receptionist reports only get to hear 1 ring or sometimes the receptionist's phone does not ring at all-this is basically my problem.

The PSTN provider has done a number of tests and concluded that their side has n o problem.

The voice-ports/dial-peers are well configured,i have counter checked the configurations and they all seem okay.

Where could i be going wrong,

Please help,this client is on my case.

Hall of Fame Super Red

Re: Please help-Ringback on PSTN

Hi Nickolas,

You may be seeing this issue due to Caller ID being enabled on the FXO;

FXO Delayed Caller ID Delivery

Before Cisco IOS Release 12.4(11)XW, Foreign Exchange Office (FXO) Caller ID in North America was delivered between the first and second ring cycles based on the Telcordia GR-30-CORE standard. FXO software was configured to wait for Caller ID delivery before initiating the call setup for the next leg. As a result, the destination endpoint did not start ringing until after 1.5 to 2 ring cycles on the FXO port.

Beginning with Cisco IOS Release 12.4(11)XW, the immediate keyword is added to the connection plar opx command. When this keyword is included in the syntax, the FXO port sets up calls immediately so that the ring-cycle discrepancy is eliminated, and the perception of the number of rings is the same for both the caller and the called party. When the Caller ID is available, it is forwarded to the called number. If the called party answers the call before the Caller ID has been forwarded, then the Caller ID update will not be forwarded to the display at the called party.


Note This feature does not require that Caller ID be enabled. If Caller ID is enabled, it is handled as described here. The fundamental benefit of this enhancement is to ring the destination party immediately.


This feature is critical for service organizations that have service level agreements (based on calls being answered within a specified number of ring cycles) with their customers.

From this good doc;

Hope this helps!


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