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New Member

FXO calls not getting disconnected


I am facing an issue after integrating PBX with 1860 Router. When a call comes in from PBX extension to a phone connected to Router (For both IP Phones and also Analog Phones connected to FXO), the phone keeps ringing even after the Caller hangs up.

The voice class defined is given below,

voice class custom-cptone ABC
dualtone busy
  frequency 425
  cadence 375 375
dualtone ringback
  frequency 440
  cadence 400 200 400 2000
dualtone disconnect
  frequency 485 625
  cadence 250 250

and the Voice port configuration on FXO Port is given below,

voice-port 0/1/0
supervisory disconnect dualtone mid-call
supervisory custom-cptone ABC
no vad
cptone IN
timeouts call-disconnect 1
timeouts wait-release 1
caller-id enable

Waiting for some valuable solution.

Hall of Fame Super Gold

Re: FXO calls not getting disconnected

How do you know the tone frequencies are right for your telco ?

Definitive solution is ISDN only.

New Member

Re: FXO calls not getting disconnected

am not sure about the disconnect frequency. But still isdn option is not there, thats why asking for a solution.

Hall of Fame Super Gold

Re: FXO calls not getting disconnected

You need to know the exact frequencies. Search forum on methods to do that.

New Member

Re: FXO calls not getting disconnected

Three Things:

1st this document, although labeled BASIC, can get very deep, very quickly.  However it will explain the idea behind troubleshooting this issue in detail if my second point does not resolve this issue for you:

2nd try to add or remove this command to your voice port:

supervisory disconnect signal


no supervisory disconnect signal

And last but not least:  here is a good page with some information on troubleshooting FXO disconnect issues.

Thomas Dillingham

Cisco TAC

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