asterisk users - Mar 2012 - "alaw = 1-2" in system.conf (dahdi) not working in UK

Hi all,

I've tried to explicitly set my two PSTN trunks/FXO lines to alaw with:

alaw = 1-2

in /etc/dahdi/system.conf. However, when I do this, all I get is loud 
intense noise on the line and nothing else - can't dial, can't make 
calls, can't receive calls. If I omit it altogether, everything works fine.

As I'm in the UK - I thought Europe uses alaw on phone lines - how come 
Asterisk seems to be using only ulaw - and alaw won't even work? Config 
examples on the Internet seem to suggest that it should work.

Thanks for any help,

Sebastian

On Sun, Mar 11, 2012 at 12:05:48PM +0000, Sebastian Arcus
wrote:
> Hi all,
> 
> I've tried to explicitly set my two PSTN trunks/FXO lines to alaw with:
> 
> alaw = 1-2
> 
> in /etc/dahdi/system.conf. However, when I do this, all I get is
> loud intense noise on the line and nothing else - can't dial, can't
> make calls, can't receive calls. If I omit it altogether, everything
> works fine.
> 
> As I'm in the UK - I thought Europe uses alaw on phone lines
No, they don't. Phone lines are analog. ulaw / alaw settings here are
internal to DAHDI. The digital PCM gets converted to analog "audio"
(voltage level) on the adapter.
>- how
> come Asterisk seems to be using only ulaw - and alaw won't even
> work? Config examples on the Internet seem to suggest that it should
> work.
Though it is, indeed, a bug.

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