[Asterisk-Users] How change default law for T100P

[Peter Svensson]

On Wed, 3 Nov 2004, Michael Loftis wrote:

> --On Wednesday, November 03, 2004 15:40 -0700 Manuel Marin 
> <mmg at transtelco.com.mx> wrote:
> 
> > I would like to know if there is a way to change default ulaw for a T1
> > card. I see in the zap show channel X that is working as ulaw. How do I
> > change it in zapata.conf or zaptel.conf to alaw. Iam interconnecting a
> > Meridian PBX but I need to configure it as alaw.
> 
> You can't.  A T1 line is always ulaw encoding.

Of course not! A T1 is just a transport pipe, you can run whatever you 
like over it. You run what is most suitable for you. Since T1 is the 
dominat line type in America the most common configuration is to run ulaw 
encoded speech on it. E1 is the dominant line type in Europe where alaw is 
the most common format and so alaw is the default for E1:s.

On a pri line the law for an incoming call seems to be set based on the 
bearer capabilities.

For other lines and for outgoing calls on a pri I think the law type is 
taken from the zaptel module default for the channel. This can be set with 
a line like
   alaw=1-23
in the zaptel.conf file. The choises are "alaw", "mulaw" and "deflaw".

Peter