T32 no audio RTP fs-1016

[Mikee]

Hi all,

i am new to the forum but my company has been using the Yealink product for many years now and we and our customers are happy about the products.
A few weeks ago we placed a T32 at a customers site an he reported audio problems ( one-way audio or no audio ).
after some testing we noticed that this only happens on internal calls. So after some PCAP traces i saw an strange thing and i think this is related to my audio problems i will explain:

For testing we placed 3 calls :

from external to yealink ( audio ok no problems).
from yealink to external ( audio ok no problems).
From snom 300 to yealink (internal) there seems to be one way audio.

I my PCAP trace i see the RTP protocol using codec g711 ( for the external calls ) audio seems to be fine no problems.
On my internal call between snom and yealink i see my snom trying to communicate using PT= ITU and codec G711 but the yealink phone uses PT=USA and codec is fs-1016.
i am not sure if this could be the problem i just noticed the change in codecs on internal calls.
i cant seem to find any settings related to he FS-1016 codec

The phone is connected on a 3cx PBX v12 and is running firmware 32.70.115.9
i hope anyone can help me out the problem is cracking my head for a few weeks now

Thanks in advance

greetings,

mikee