[Asterisk-Users] sound problem, please help!

[Esteban Maestre]

Hi all!

I have a strange problem when using asterisk. I have configured asterisk
to receive calls (FX0). In my configuration, I want asterisk to play music
while  I record the caller's speech. If the caller does the call from a
fixed line telephone, there is no problem, but in case the caller does the
call from a mobile GSM phone, the quality of the music he hears becomes so
bad, and even more when he speaks.
I have tried several codecs.
Any idea or advice?

thanks in advance,

-esteban-