Hi thanks for your replies, I am not sure if the telco supplies disconnect supervision; I am making test because I have a problem with the externals calls coming from the pstn trough the fxo ports: if the external phone?s user (caller) terminate the call before the ip phone user (called) hang up the call, the ip phone continues ringing and the fxo port continues off hook; the call is not correctly ended.

Have you got any ideas of the cause of the problem?

Indeed the problem is caused by lack of supervisory disconnection. If the telco sends a tone on caller hang-up, you can try supervisory tone disconnection as indicated in the above document.

Hi, thank for your help I have tried the solutions indicated in the document but it still don?t work, I have now this configuration:

!

voice class custom-cptone dz

dualtone disconnect

frequency 425

cadence 500 500

voice-port 0/0/0

supervisory custom-cptone dz

cptone FR

timeouts interdigit 3

timeouts wait-release 15

timing hookflash-out 500

impedance complex2