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User does not hear a busy tone when a PSTN call is terminated on a Cisco voice gateway


Core Issue

A call from a Public Switched Telephone Network (PSTN) through a gateway to a Cisco CallManager IP phone, Cisco IOS  gateway, or third party H.323 device, may not get a busy tone when running either an application or two-stage dialing on the originating gateway.

Note: Two-stage dialing refers to the calling party dialing the number to the gateway first,    receiving the dial tone, then dialing the called party.

In either case, the call has connected in terms of the PSTN network once it terminates on the originating gateway. If the IP call leg comes back with a release with the user busy cause, the message cannot be indicated back toward the Telephony session that is in a connect state.


This issue has been addressed by having the originating gateway generate a busy tone    when the release from the IP call leg is received with a cause code of user busy. The telephony leg will either be released by the calling party or by the    gateway after several minutes with the cause code of normal call clearing .

This feature is available in Cisco IOS Software Release 12.2(8)/12.2(8)T and later.

For more information, refer to Troubleshooting No Busy Tone and No Announcement Messages on ISDN-VoIP (H.323) Calls.

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