I am using 2851 to transcode G.711 to G.729 by SIP. When the SIP call reaches 2851, it responds 100 Trying, then gets "501 Not Implemented" Error and call dropped.
When I tried SIP to H.323 transcoding it works fine. I allowed the SIP to SIP in Voice service. What's should I rectify this problem? Thanks!
allow-connections h323 to h323
allow-connections h323 to sip
allow-connections sip to h323
allow-connections sip to sip