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New Member

Incoming ring problem

Hi,

I have a very bizzare issue where one of our lines rings twice pauses for 5 seconds and then starts ringing again. The caller hears no disruption in ringback. The line in question is our main line to the branch, all PSTN lines come in on FXO ports, our phones are 7940's and 7960's. Gateway is a 2811 H323. Call Manager is 4.1.3. The weird part is all 11 other lines at the branch are configured exactly the same way and do not experience this issue. I've taken the line itself out of the router and plugged in an anlog phone to double-check that the issue is not on the telco side, but it works fine. I've run a few debugs, but to be honest it's kind of hard for me to interpret what I'm seeing, nothing obvious jumps out at me.

I've attached a "debug voice ccapi inout" and "debug dial peer". During the debug, I made a phone call to the branch (extension/main line 0727312); on the branch side, it rang twice, disappeared for 3-5 seconds, then started ringing again; an employee answered and then we hung up.

Thanks so much!

Keli

1 ACCEPTED SOLUTION

Accepted Solutions
Bronze

Re: Incoming ring problem

Here are 2 possible causes.

(1) The polarity on the wires are reversed - please verify this and swap if necessary

(2) The incoming wire is 4-wire instead of 2-wire. Cisco recommends having 2 wire. The circuit on the fxo boards are more sensitive than regular analog phone, and thus strange behavior can occur if it is physically 4 wires.

Also, there may be signal coming in on the line, so please gather "debug vpm signal" and see if something like battery-reversal is being induced from the provider.

Thanks,

Tony

5 REPLIES

Re: Incoming ring problem

Have you tried moving the main line to one of the other FXO ports. Maybe there is something wrong with the port it's self. Also what version of IOS are you running?

New Member

Re: Incoming ring problem

thank you, yes I tried that and there was still the same issue

Bronze

Re: Incoming ring problem

Here are 2 possible causes.

(1) The polarity on the wires are reversed - please verify this and swap if necessary

(2) The incoming wire is 4-wire instead of 2-wire. Cisco recommends having 2 wire. The circuit on the fxo boards are more sensitive than regular analog phone, and thus strange behavior can occur if it is physically 4 wires.

Also, there may be signal coming in on the line, so please gather "debug vpm signal" and see if something like battery-reversal is being induced from the provider.

Thanks,

Tony

New Member

Re: Incoming ring problem

Thank you, I will check this out and post my reply soon.

New Member

Re: Incoming ring problem

that was it! I did the vpm signal debug and saw battery reversal messages. I entered a "no battery-reversal" command on the voice port and the problem disappeared. Thank you very much for your help!

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