[asterisk-dev] Asterisk mishandling user busy isdn releases

[Klaus Darilion]

Ken Leland III schrieb:
> Hello All,
> I have found that Asterisk does not play a busy tone when it receives a 
> USER BUSY ISDN RELEASE messages following an ISDN CONNECT message.
> 
> Details:
> We are connecting our Asterisk PBX to a Lucent telephone switch via ISDN 
> PRIs.  The telephone switch provides an authorization code feature where 
>   every call originated from asterisk is immediately answered by the 
> telephone switch, and prompted for an authorization code, before 
> completing the call.  The sip phone registered with Asterisk dials a 10 
> digit number, hears the prompt, and dials a 4-digit code.  The telephone 
> switch authenticates the code and attempts to complete the call.  In the 
> event that the far end is available the telephone switch passes the 
> ringing tones inband over the pri.  In the event that the far end is 
> busy,  the telephone switch sends an ISDN RELEASE message with the 
> cause: USERBUSY.  Asterisk receives the RELEASE message and sends a BYE 
> message to the sip phone and a RELEASE COMPLETE back to the switch. This 
> does NOT result in the user hearing a busy signal.  Instead, the user 
> hears a click and dead air as if they were hung up on.
> 
> Questions:
> Is there a way to configure this behavior in the dial plan?

You can check DIALSTATUS after Dial() and play Busy() if the DIALSTATUS 
is busy.

klaus


> 
> If not does anyone think that adding the following logic to Asterisk 
> would be a useful patch?
> 
> If a zap channel is bridged with a sip channel, and the zap channel 
> receives a user busy RELEASE, play a busy tone inband on the sip channel.
> 
> Cheers,