asterisk users - May 2007 - wait for rings, answer on outdial via SIP

Hello,

I am working on an outdial project and the Asterisk box is connected
behind a PBX via SIP.  When a call from the Asterisk box is routed out
over the PRI attached to the PBX I am not getting proper call progress.
The PBX is indicating that the call is answered while it is still
ringing at the far end.

Does anyone have any suggestions on how I should go about waiting for a
variable number of rings followed by the answer before playing my
outbound greeting (over a SIP channel)?  NVLineDetect looks like it
would work for this but I'm not sure if it's still supported and/or
distributed.

I am using BackgroundDetect to wait for the greeting ("hello," etc.)
following the answer.  I just don't know how to deal with the variable
number of rings.

Any help would be appreciated.

Barry

On Fri, 25 May 2007, Barry Porch wrote:
> I am using BackgroundDetect to wait for the greeting ("hello,"
etc.)
> following the answer.  I just don't know how to deal with the variable
> number of rings.
   This problem or may not have a good solution, but if it does, it's
probably bound up in some subtle intricacy of the ISDN Q.931 signaling
and progress indication over the PRI from the PBX.  It is entirely 
possible that the PBX is sending back an ALERTING message (which means
that the far end is ringing) in a precise and timely fashion but
Asterisk is failing to appropriately recognise that for what it is.

   Another possibility, given what you said about how Asterisk perceives
the call to be immediately answered, is that the PBX "answers" the
call
from an incoming internal trunk (from an ISDN standpoint) and then
cross-connects the media with the goings-on of another leg it builds out,
in such a way that immediate pickup is quite literally what's taking
place from the interior.

   I know of no way to detect ringing feedback acoustically in connection
with Asterisk

--
Alex Balashov
Evariste Systems
Web : http://www.evaristesys.com/
Tel : +1-678-954-0670