When we send calls to an Adtran gateway, our calls using g.729 work properly. I noticed in the SDP the following field:

a=fmtp:18 annexb=yes

When we send calls to a Cisco gateway, the same call fails.

Inbound g.729 calls coming from the Cisco gateway work properly and I noticed the following:

a=fmtp:18 annexb=no

Is there a way to set this parameter in the dial-plan or sip profiles so we can match what the Cisco gateway is looking for?

Thanks,

Ken Fulmer