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New Member

Busy tone after ISDN DISCONNECT message

I have Cisco CallManager 4.1(3) and Cisco 2811 router as a gateway between VoIP and PSTN. Cisco 2811 fowards all calls that begins with "9" to PBX. It's simple and traditional design, isn't it? Here is the dial-peer:

dial-peer voice 9 pots

destination-pattern 9T

translate-outgoing calling 34000


port 0/0/0:15

forward-digits all

The problem: users don't hear busy tone when a PSTN number is busy. Telco sends DISCONNECT message through ISDN (with cause i = 0x8091 - User busy) and CCM just drops the call :(

How do I make CCM (or gateway?) to generate busy tone to Cisco IP phone users?

P.S. I've employed "voice call convert-discpi-to-prog always" command - no effect. I've also turned on "Retain Media on Disconnect with PI for Active Call" option in CCM. Nothing changed.


Re: Busy tone after ISDN DISCONNECT message

I think there are no available channels for the call to complete

New Member

Re: Busy tone after ISDN DISCONNECT message

i dont think so, because the call is outgoing, so if the PBX sent the DISCONNECT/busy its because :

a.- The PBX dont have a channel available to make the call out to the PSTN

b.- The final user its occuping its phone

The real problem its that the Gw dont recongnize the BUSY signal and simply drop the call, i had the same issue, and we need to change from PRI to QSIG, and the issue was resolved.

I hope it help....




Re: Busy tone after ISDN DISCONNECT message


Router(config)#voice rtp send-recv

Router(config)#voice call send-alert

Telco should send Disconnect with Cause IE = User Busy.

He can include a Progress IE = 8, in this case and with the command configured :

voice call convert-discpi-to-prog

This Disconnect will be mapped to Progress, Voice path will Cut Thru and IP phone will hear busy tone send by PSTN.

Does he send a Release Complete after Setup or do you also see the Call Proceeding?

Also, including a PI = 3 in the outgoing Setup can help.

In this way we are indicating to PSTN we are a NON-ISDN terminal and need info INBAND.

configure following on the Outgoing POTS :

progress_ind setup enable 3


progress_ind alert enable 8

As long as the Telco does not send the correct Cause IE we will not hear a busy tone although this is not the case.

A debug voice ccapi inout will be great.

Let us know

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