FXO Port disconnect issue.

[Jawad Ahmad]

Hello all, 

I'm facing a issue in our network, We have 10 analog line with one pilot number. Incomming and outgoing calls are working fine only problem when any one call from outside to our network if operator doesn't respond, call disconnect from mobile site but its still showing connected on port and phone continuously ringing. Until shut un shut the port remove the line in router or off hook the phone. 

How I can troubleshoot this problem which debugs I need.

You can find running config in below attached file.

[D_Lebedev]

Hi Jawad.

We're using FXO also on our site.

When i've faced with same problems with disconnect issues,i'd no luck with changing cadense and cp-tone parameters at all.

So,what i can advice you-use hardware busy tone detectors.

Couple of years ago i spent couple of months,but.as i wrote already there is no way solve this issue with config and IOS commands-only hardware BTD devices will help.

[Jawad Ahmad]

thank you for you reply.

What is BTD devices how I can use these devices.?

[D_Lebedev]

BTD= Busy Tone Detectors.

There is a lot of vendors with own equipment.

We're using russian one,called BTD-24

As a rule it's device which monitors line state.

You'll have connect it between PSTN and PBX(FXO)

Like that:

PSTN pair---BTD input pair---BTD output pair---FXO pair

This device monitors line state.When there is busy tone from PSTN side,it makes physical disconnect to the line.and after few seconds the line is free again,FXO goes to on hook state.

You can find out which type of BTD in stock near your place.

There are mainly 2 types of BTD-with console management for some program adjustments and simple,just plug and forget.

If you have 10 lines at this time,you'll need obtain 12 port BTD or 24 port for future grow.

[Jawad Ahmad]

Thank You.