Question about CODEC, How to config server does not convert codec via Asterisk sip server

[BlakeChen]

My Test Enviorment
A(Wireless Route Have SIP Fumction and CODEC order is G711A/G711MU/G729)
B(Wireless Route Have SIP Fumction and CODEC order is G711A/G711MU/G729)
Asterisk sip server(CODEC order is G711MU/G711A/G729)
A call B
Current results
The Asterisk sip server will convert codec to G711MU

Expected results
Wireshark captures RTP packets with G711A.

[david551]

The easiest option is simply to delete A-law and G.729 from the list of Asterisk codecs. Otherwise, you are going to need to tell us the channel driver, the options used, and provide a listing of the SDP exchanges on both sides. The Asterisk version may help, and adding debut level 5 to the pjsip set logger on/sip set debug on command should give further information.

Also, I think we need the rtp debugging, as it isn’t clear which sides of Asterisk are using µ-Law.

Note that codec orders are only hints, and devices can ignore them, or choose whose order to use.

[BlakeChen]

@david551

Otherwise, you are going to need to tell us the channel driver, the options used, and provide a listing of the SDP exchanges on both sides

Thanks for u reply.
So the codec orders is depend on device?
Beacuse in my case.
I need to test my Device codec order is workable.
So delete A-law and G.729 is inadequacy.
When A call B, the packet can see codec orders is same as my settting in Invite Packet.(G711A/G711MU/G729)
But through the server, the codec was reorder to G711MU/G711A/G729.
Any config in sip .conf can be configuration?

Thank you again for sharing information with me.