FXO Disconnect Problem

Question

Hello,
I just would like to ask some ideas on FXO disconnect problem having a setup of FXO to FXO termination on both sites. I am using a VIC-2FXO-M2 on both Cisco 1760-V Router and these fxo ports are terminated to the PABX local.The voice port will disconnect 30minutes (approximately) after the call is terminated or it remainded off-hook although the call is already done.
We tried some fine tunings like enabling "battery-reversal" command, setting the timeout call disconnect to 5sec, timeout wait-release to 5sec. But the problem is still the same.
What is really the ideal fxo disconnect solution that we can do to lessen the 30minutes delay from off-hook to on-hook.
Looking forward for your great ideas.
Thank you.
Vivira Alastra

Answer 1

Dear Vivira,
The disconnection issue of FXO ports can really produce some gray hairs...
I have worked integrated to some cheap Panasonic PBX's in Nigeria where documentation is really scarce.
The solution that worked - but don't ask me how - was to try different combinations of CPTone on the Voice Ports. That did the job in our case.
You can also try the tedious job of measuring the disconnect tones ans analyse it e.g. in CoolEdit and then set up a Voice Class where you define the tones.
But try the CPTone settings first.
Good luck.
Peter