Thank you for your answer.
I have set disallow=all
allow=alaw (we use alaw in europe)
In my company inside i want to use g722.
So i set my extensions with disallow=all and allow=g722&alaw
But my phone calls out everywhere with g722.
Asterisk is transcoding the call to alaw.
core show transcode says my transcoding time from g722 to alaw is only 12ms.