When FXO port is called from PSTN, Cisco phone continues to ring

melinda.clancy · ‎02-17-2010

I have a 2 - 2 port FXO modules. On one of these I have two lines from PSTN. Both ports are configured the same (as far as I can tell), port 1/0/1 works fine, but port 1/0/0, when a call is received continues to ring even though the user (Cisco phone) has answered. The caller continues to hear ringback, but the user can faintly hear the caller talk. I have switched the connection from the PSTN and the problem stays on that port. So I know it is not the line cord, jack, or problem with the business line from the PSTN.

Any idea? Please let me know.

Thank You,

Melinda

Rob Huffman · ‎02-17-2010

Hi Melinda,

This is refered to as "Answer Supervision" here is a doc that details this feature

FXO Answer and Disconnect Supervision

http://www.cisco.com/en/US/docs/ios/12_2t/12_2t2/feature/guide/ft_ansds.html

Sometimes is simple shut/no shut on the port can alleviate this problem.

Hope this helps!
Rob

melinda.clancy · ‎02-18-2010

Rob,

Thanks for the reply!

I did read up on this before posting the question and thought I understood that it was either Battery Reversal or Answer/Disconnect Supervison needed to be set. Both ports (working and not working) are set to Battery Reversal. Since the port that is working is set to Battery Reversal, I didn't think that was the problem. Do you think I should change the port that is not working to Answer Supervision and if it works, I will be confused?

Also, I have done the shut/no shut on the port.

Please let me know your thoughts.

Thanks,

Melinda

melinda.clancy · ‎02-18-2010

Rob,

I just changed the port from Battery to Answer Supervision and had the same result.

I thought about reseeding the FXO module?

Please let me know.

Thanks,

Melinda