Asterisk withing with cisco 5400

My asterisk keeps pop this info:

Feb 12 15:18:25 NOTICE[xxxxx]: rtp.c:330 process_rfc3389: Comfort noise support incomplete in Asterisk (RFC 3389). Please turn off on client if possible. Client IP: xx.xx.xx.xx

This client IP is the cisco 5400 which is the main terminal that we terminate all phone calls.

I’ve already put “no nad” for the connection link cisco and asterisk but seems nothing happened. Voice still chopping. Anyone have idea how to fix it?