[Asterisk-Users] PRI/Zap premature dialing problem

[Peter Svensson]

On Mon, 6 Dec 2004, Kris Boutilier wrote:

> The originating PRI system passes the entire dialed number in the d-channel
> setup frame, thus the concept of a wait time for additional digits is
> meaningless. Progressive digit gathering implies that the signalling is
> occuring 'in-band' as would be the case with DTMF signalling on analog
> lines.

This is incorrect. Isdn (and thus pri:s as well) can and often do use 
overlap dialing. This is very much out of band in the d channel. I have 
not seen a pri that listened inband but that may be possible as well.

Asterisk can be configured to allow overlap diling on a pri span. It will
still support enbloc diling if overlap is enabled. 

> You need to look in the Ascom and find the configuration table that lays out
> the dialplan for the network. The PBX itself will use that information to
> determine that for example, if a number begins with '4' then it is
> 'complete' after a total of 3 digits (eg. 411) or if it begins with 1, then
> it's complete after 10 digits (1XXXNNNXXXX). After the number is considered
> 'complete' it will build the setup frame and transmit it to the terminating
> system. 

Fixed numbering plans are broken in so far as you cannot know the 
numbering plans of all the countries in the world. Some countries have 
variable length numbers as well. 

Use overlap dialing and let the PSTN sort things out via ss7. Asterisk 
already supports it.

Peter