[Asterisk-Users] Help - is voip good for in-house calls?

[Peter Svensson]

On Wed, 18 Aug 2004, Darryl Ross wrote:

> > Oh, so I how does Asterisk knows when to start dialing out the
> > numbers, if there are no rules?
> 
> Have a look at http://www.voip-info.org/wiki-Asterisk+Extension+Matching

It doesn't actually tell the whole picture. There are two ways to handle 
variable length phone numbers whose length are not easily predicted. This 
can be numbers in the national dial plan for e.g. Sweden and Germany and 
also for international calls.

One way is to allow Asterisk to collect digits until some event signals 
that the number is complete. This can be a timeout or a hash sign, I 
think. Asterisk then dials the whole string at once. This is called 
"enbloc dialing" and has the advantage of being supported by all 
underlying transports.

The other way is to hand off the call to the pstn as soon as you know that
is where it is headed and just pass the digits to the pstn after that.  
This is called "overlap dialing" and is how most users are used to the
pstn working. This works for at least the zap channels. There is support 
for overlap dialing in Asterisk but it is not perfect yet. We use it but 
we needed a few hacks to the code. 

I hope to have the time to create a good patch in a few weeks time. Right 
now we are too busy to have time to experiment with our main pstn 
connection. 

Peter