asterisk users - Apr 2012 - DAHDI FXO Call Issues / Indication Types

Greetings-

I've had reports of a customer PBX acting strangely to some inbound calls.
Specifically, a call comes into an FXO port, hits a Dial() to ring a few
extensions, but by the time someone answers the phone, the call has been
dropped, and the caller is listening to on-hold music. There is nothing in the
dialplan that would cause this behavior.

The logs have a couple of odd (to me, maybe normal) items that may give some
information.

After the call comes in, and the SIP endpoints are dialed, I see:

[2012-04-12 08:51:04] DEBUG[7313] chan_dahdi.c: Requested indication 3 on
channel DAHDI/1-1

I have to assume indication 3 means playing ringing tones to DAHDI/1?

The phones are ringing at this point. In the logs I see this:

[2012-04-12 08:51:06] DEBUG[7313] sig_analog.c: analog_exception 1
[2012-04-12 08:51:06] DEBUG[7313] sig_analog.c: Exception on 13, channel 1
[2012-04-12 08:51:06] DEBUG[7313] sig_analog.c: __analog_handle_event 1
[2012-04-12 08:51:06] DEBUG[7313] sig_analog.c: Got event
ANALOG_EVENT_RINGBEGIN(12) on channel 1 (index 0)

I'm assuming the indication 3 specified earlier was to send ring tones on
DAHDI/1, this simply confirms it?

Next, one of the phones answered the call, and a new indication is sent:

[2012-04-12 08:51:07] VERBOSE[7313] app_dial.c:     -- SIP/102-000021ae answered
DAHDI/1-1
[2012-04-12 08:51:07] DEBUG[7313] chan_dahdi.c: Requested indication 22 on
channel DAHDI/1-1

What does indication 22... indicate?

There is more to the log, but it is intermingled with a callback and I'm not
easily able to parse it out at the moment. Does any of the above seem out of
place, or does it look 'normal'?

As an aside, where could a person find a list of indications used on DAHDI
channels, analog and/or PRI/T1?

--Tim

I'm not a chan_dahdi expert but I thought I would take a crack at
answering your questions...

On Thu, Apr 12, 2012 at 11:31:37AM -0500, Tim Nelson
wrote:
> Greetings-
> 
> I've had reports of a customer PBX acting strangely to some
> inbound calls. Specifically, a call comes into an FXO port, hits a
> Dial() to ring a few extensions, but by the time someone answers
> the phone, the call has been dropped, and the caller is listening
> to on-hold music. There is nothing in the dialplan that would
> cause this behavior.
> 
> The logs have a couple of odd (to me, maybe normal) items that may
> give some information.
> 
> After the call comes in, and the SIP endpoints are dialed, I see:
> 
> [2012-04-12 08:51:04] DEBUG[7313] chan_dahdi.c: Requested indication 3 on
channel DAHDI/1-1
>
> I have to assume indication 3 means playing ringing tones to DAHDI/1?
This is letting chan_dahdi know that the SIP phones are ringing.