Thanks for answers.
No DTX_UL, no Pwrctrol.
Will try to use one Codec.
I saw some discussions about TFO and AMR, do you think this could bring codec mismatch ?
For a fact, i remember with Nortel we had the same problem where one codec (4.75) was not working properly.
Here, most of the time it is the 12.2 AMR_FR that is used, normally this should give a good quality.