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New Member

Disconnect tone on FXO port

Hi All,

Whenever the outside caller hangs up, the FXO never hangs up.

Our setup:

IPCC---CCM5.0.4----c3845(w/ vic2-4FXO using mgcp)

A call comes in on fxo ports configured as mgcp endpoint. CCM configured with unattended DN passes call to the IPCC CTI_RP. Whenever the outside caller hangsup, FXO never disconnects and script still playing. Tried to redirect to an ip phone and same results. IP phone keeps ringing.

We recorded the disconnect tone on the line.

Problem is, after configuring custom disconnect tone, it doesn't seem to work at all.

Can somebody translate this for me? Maybe i misinterpreted the frequency or cadence that i used.

250ms on

250ms off

Tried Freq of 485HZ and 477HZ with no luck. Is the freq i used correct?

voice class test

dualtone disconnect

frequency 477 477

cadence 250 250

voice-port 0/2/1

supervisory disconnect dualtone mid-call

supervisory custom-cptone test

no battery-reversal

timeeouts call-disconnect 3

timeouts wait-release 3

Any chance mgcp might cause problem with custom disconnect tone?

We are using ios of 12.4(12) ip voice feature set if this info is needed.

Any inputs are welcome.



Hall of Fame Super Gold

Re: Disconnect tone on FXO port


where are you located? If in North America, chances are that your telco can configure the lines for ground start or power denial. Either method would ensure faster and faster disconnect that tone detection.

Else again I can look and compare the disconnection tons with a frequency analisys.

New Member

Re: Disconnect tone on FXO port

I am located in the Philippines.

Telco is unable to provide ground start and power denial being the default config before don't work.

Tried using the freq and cadence with no luck.

Not really sure which telecom company here if referring to.

Another problem is that the telco here is uncooperative or they also don't know what freq and cadence they are sending the disconnect tone. Leaves me with detecting the disconnect tone option.

I used an internal modem to record the disconnect tone. I hope the tone is clear.


Hall of Fame Super Gold

Re: Disconnect tone on FXO port


On disconnected2.wav,

The first tone is 440 Hz continuous.

The second tone is 480+620 Hz, 250ms on 250ms off, reported as congestion by 3am.

The third, is 1400+1800 Hz 200ms on, 300ms off, report as howler by 3am.

Hope this helps, please rate useful posts with the scrollbox below!

New Member

Re: Disconnect tone on FXO port

i see. So it is the congestion tone not busy tone. I used the busy tone last time.

Let me try congestion tone this time.

I tried the Howler tone as the disconnect tone but didn't disconnect. i'll tweak the timeout to 1 sec and test.

If all else fails, maybe will open a tac case since we have the freq and cadence now.

Thanks for the analysis and assistance.

New Member

Re: Disconnect tone on FXO port

works great. Had to lower the timeout to 1 so that it will disconnect the line quick.

now i know how to analyze it will cooledit as well. Thanks a bunch!

New Member

Re: Disconnect tone on FXO port


can you please help me too to identify this tone?

i am trying to configure one cisco gateway in jordan and call diconnection is having problems.

i would really appreciate your help.



New Member

Re: Disconnect tone on FXO port


How can i record the disconnect tone? am having the same problem with MGCP controlled FXO ports on 2801 and CCM 5.1.2?



Hall of Fame Super Gold

Re: Disconnect tone on FXO port

Place your PC microphone close to the handset, and record the tone. Please do that in a silent environment.