asterisk users - Jun 2006 - Problems and questions with setting up a Feature Group D trunk to a Nortel DMS-10 switch

I currrently have Asterisk 1.2.8 with a TE110P Zaptel card tied to our Nortal
DMS-10 switch via T1.

This T1 trunk is configured for Feature Group D MF.

The purpose of this is for LD delivery to a VoIP LD provider as a LD choice for
our customers off of the DMS-10.

When I sieze a channel on the zaptel, I get a spill of digits from the switch
that is the called number, and I can see that in asterisk as the ${EXTEN} and
the switch is stripping the 1, so I see NXXNXXXXXX from the switch.

Supposedly after I get the called number spill from the switch, I'm supposed
to wink the trunk and then get an ANI spill of the called-from number.

I'm at a complete loss as to what to do. There are no good examples that
I've been able to find on how to wink and grab the ANI digits from the
switch, or if asterisk does this automagically and hides the digits in a
variable somewhere. The only references I've found to ANI in the documents
refer to PRI, and Feature Group D is a E&M trunk.

I don't even have to worry about calls coming from the VoIP network back to
the DMS-10.. I only need to forward outbound calls from the switch to the LD
VoIP provider.

Thanks in advance for any help!

John Fulton
Anchorage, AK

----- John Fulton <jfulton@arctic.net> wrote:
> I'm at a complete loss as to what to do. There are no good examples
> that I've been able to find on how to wink and grab the ANI digits
> from the switch, or if asterisk does this automagically and hides the
> digits in a variable somewhere. The only references I've found to ANI
> in the documents refer to PRI, and Feature Group D is a E&M trunk.
If this signaling mode is supported, it will be entirely inside chan_zap, not
something you will do in your dialplan.

It does not appear there are any signaling modes in chan_zap that send a wink in
between receiving the called number and the calling number (ANI); the FEATD
modes send a wink, wait for a digit string (which they expect to be in the
format *NNNN...*NNNNN...*) and then send a final wink to acknowledge the receipt
of the dial string. The digit string is then split into called number and
calling number and the call process continues.

-- 
Kevin P. Fleming
Senior Software Engineer
Digium, Inc.

----- John Fulton <jfulton@arctic.net> wrote:
> Now, in the ${EXTEN} variable, what should I see at that point?
> Currently it looks like I am just seeing 8155555678. Would the ANI
> field show up in a different variable?
Yes, as the Caller ID number, so ${CALLERIDNUM} or ${CALLERID(number)} depending
on which version of Asterisk you are using.
> I never hear the digits read back to me, I get a recorded message from
> the Nortel saying "There is a temporary problem with the Long Distance
> carrier you are calling. blah.blah.blah"
Probably you will want to use featdmf instead of e&m as your signaling mode,
that will properly parse the incoming digits and also send the acknowledgement
wink. There are quite a few featd choices available in zapata.conf, so you may
just want to try them all :-) In the worst case, you can contact Digium Support
on Monday and they will be happy to help you get the signaling set up correctly.

-- 
Kevin P. Fleming
Senior Software Engineer
Digium, Inc.

----- John Fulton <jfulton@arctic.net> wrote:
> I do use "featdmf" in the zapata.conf.
> 
> In the zaptel.conf, it says to use the e&m setting for Feature Group 
> D, there is no featd setting in there.
Right, sorry for the confusion. It sounds like you have both files configured
properly.

-- 
Kevin P. Fleming
Senior Software Engineer
Digium, Inc.

I was having problems with a Feature Group D trunk into a Nortel 
DMS-10 switch in our Nome office in Alaska.

After receiving the digit spill with the called number, and calling 
number (ANI) from the switch, Asterisk would wink the switch and then 
the switch would hang up on the trunk.

After a TON of debugging, many days on the phone with Digium, and 
watching a T-berd, we discovered a timing issue with Asterisk that 
was slightly out of spec.

After the LD provider (Asterisk) sends the acknowledgement wink for 
the digit spill, the LD provider is supposed to wait on-hook for 
250ms before going off-hook. Asterisk was immediately transferring 
control of the call to extensions.conf after the wink which executed 
Answer() within 50ms causing it to go off-hook too soon.

To fix the problem, all I had to do was add a 300ms wait before 
executing Answer():
[default]
exten => _X.,1,Wait(.3)
exten => _X.,n,Answer()
...........
I hope this helps anyone else that may run into this problem.

John Fulton
TelAlaska Inc.
Anchorage, AK
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