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Automated attendant continues to ring phone after hangup


I setup a call handler that transfers to user extensions fine. If the caller enters an extension number after the greeting they get transferred to the number, but if they hang up before the call is answered the recipient phone continues to ring. I am using cucm and cu 6.

20 Replies 20

Hi Anand

I am not sure about your setup , This is just a testing scenario to try to put the CUC out of the equation and check if it will affect the call behaviour. You can setup a testing Handler and check the two option.

Also I believe as well it is important to check at the Voice gateway level by monitring the FXO behaviour when devlieving calls to both unity and a normal extension and debug at that level . Debug VPM signal and voip ccapi out as Jonathan suggested can show you the difference.

thanks jonathan, the debug commands definitely showed the fxo port not going on-hook after the caller hung up. I read the article and the following worked for me, if anyone could explain why.. i'm not sure why it worked but the issue is now resolved.

before i had

voice-port 2/0/0

connection plar opx 2500

then i entered

no supervisory disconnect signal

this entered the following in my config:

supervisory disconnect anytone

so my final config looks like:

voice-port 2/0/0

supervisory disconnect anytone

connection plar opx 2500

Can anyone explain why this works now ?

Hi Anand

FXO interface on a router acts as normal phone from the Carrier switch prespective or PBX. The FXO will close the Look for Off-hoik signaling indications , and the Switch will provide a battery current as there is no disconnect supervision from the switch side as it expects the other end ( FXO) to be a normal phone and should hang-up  when the call is terminated or abandoned. FXO expects the switch to direct it for the disconnection ( by removing battery current flow ) so it can go on-hook.PBX some times provide Power-denial , battery polarity reversal , or disconnection tone to denote the disconnection of the session from the far end.

In your case the FXO port need to have the disconnection method defined . I belive when you tried disconnection tone command this instructed the FXO port to listen to different tone frequencies during the call setup to disconnect the call once it is abandond or disconnected by the far end.

For more details about the FXO disconnection methods refer to

You can try to make Jonathan's comment the correct answer , and if this answer helped you i appreciate if you rate it

i had to revert to my original configuration when i realized that if i make an outgoing call to a phone on pstn, the recipient phone rings once then the call gets disconnected. removing the supervisory disconnect anytone solved the issue, but i am back where is started.

i came across the above link to figure out the frequency used in the pstn line.

I Placed call from pstn to IP phone. The article says to Hang up on the FXO and listen to the disconnect tone for 10 seconds.

but when i press "end call" on the pstn phone, i hear a 1 second disconnection tone and then a recording. so this would not work

for me either this method.

Hi Anand

It is also worth checking if you are having other disconnection methedology as well ( like power denial or battery reversal). Re-check the site

my card does not support battery reversal, and power denial was the default setting. i am trying to see if i can use tone frequency for disconnect.

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