[Asterisk-Users] Incoming Zap channels not behaving as expected. Rejecting call on channel....

[Beau Hargis]

On Mon, 2006-01-09 at 22:41 -0500, C F wrote:
> On 1/9/06, Beau Hargis <beauh at bluefrogmobile.com> wrote:
> > I have been messing with Asterisk for months and got it working well
> > with a SIP connection, but this is the first time I have set it up with
> > TDM cards. The cards are configured, working and the T-1's (configured
> > for PRI/DCHAN) and I can even call into it if I add the DNIS as an
> > extension to default context. That is the oddity.
> 
> It's not odd, as to Asterisk a T1 is just another interface (just like
> your SIP phone), so when it rings (it doesn't actualy ring, it just
> singals an incoming call) the T1 supplies the DNIS (AKA DID) as the
> extension it wants to dial. Asterisk then looks in the context where
> the T1 starts if the extension exists.

Sounds logical in the context of Asterisk itself. I just wanted to make
sure that it was indeed supposed to work like that.

> >
> > I can find nowhere in the documentation that says anything about having
> > to create separate extensions for all the DNIS that are assigned to the
> > trunks. The message I am getting when I follow the docs on configuring
> > zapata and the dial plan is this:
> >
> >     -- Extension '2061234567' in context 'default' from '206987654' does
> > not exist.  Rejecting call on channel 0/16, span 4
> >
> > When I add '_206XXXXXXX,1,Goto(demo,s,1)' I can get it to work.
> 
> This is what it should do, since it has no extension defined for 206987654.
> 
> >
> > This is going to be for an IVR application not a PBX. So, numbers are
> > routed down the trunks and the machine picks up and runs the application
> > assigned to the DNIS that came down the line. And, I am getting the
> > right ANI (CALLER_ID) and DNIS (Number Called). Problem is that if I
> > have to configure every DNIS, or a pattern for them, I cant have a fall
> > through.
> >
> 
> Well, you want the provider to decide where it starts? how so? oh, I
> know how, using DNIS. The provider is telling you what the caller
> dialed (DNIS) otherwise you pick up with IVRa for a call meant for
> IVRb, now Asterisk has to be configured to do something with it (it
> being the number dialed).

I was expecting it to drop into the s extension in the default context
as was configured in zaptel. It is obvious that a hardphone on someone's
desk has an extension when it is hooked up to asterisk as a PBX, but I
am coming from working with other IVR systems going back to the early
90's and the it has worked has been that a call comes in on a trunk and
there is a DNIS (DID) routing table that starts an app or context. The
concept of an extension is relevant for a PBX, but seems to be adopted
to allow incoming calls on a T-1 trunk. I am used to DID's being routed
to applications, not being treated as an extension.

> > Is this how it is supposed to behave? From all the docs I can find, it
> > doesn't seem so. Seems to me that the s extension in [default] should
> > work. What are other people's experiences hooking up TDM hardware for
> > incoming calls?
> >
> 
> The s extension will only be used if no extension is given and there
> is an incoming call (like when asterisk dials using:
> Dial(tech/resource) without anything after the resource). On POTS it
> means every incoming call since there is no means of signaling what
> extension (other then using DTMF). With PRIs if there would be a
> signal for an incoming call, but no DNIS is received then it would
> also start at s. However in your case there is an extension coming in,
> it's the same as dialing from a sip phone connected to your Asterisk
> box 206987654. There must be an extension defined for this to work.
> The documentation is everywhere, its just the misunderstanding that a
> T1 is special, while it is in terms of the signalling, it is NOT
> special in any other way, including the way Asterisk sees it. Once
> configured Asterisk sees it as whatever the logic of the contexts you
> have setup on that box. But from the point of view of a device, as
> long as there is an extension coming in it has to be defined,
> otherwise asterisk will look for the i extension.

This is just not obvious from reading the documentation for months. I
have written my own app modules for asterisk in the last couple of
months, so it's not like I am not familiar with the internals of how it
works. It's just still odd to think of building IVR apps the way
asterisk works as a PBX, even if asterisk is more flexible and powerful.
Still a hell of a lot better than the alternative.

Thanks a lot for the input. I can tell everything that it's actually
working and not b0rked.