Hi all This is my network schema: h323endpoint1..10 <=>gk1<=>gk2<=>h323/sip GW<=>SER<=>asterisk<=>sip endpoints When I use the voicemail options with calls between h323 endpoints in asterisk, I obtain the following error: Dec 5 16:14:40 NOTICE[10528]: rtp.c:564 ast_rtp_read: Unknown RTP codec 96 received Dec 5 16:14:40 NOTICE[10528]: rtp.c:564 ast_rtp_read: Unknown RTP codec 96 received Dec 5 16:14:40 NOTICE[10528]: rtp.c:564 ast_rtp_read: Unknown RTP codec 96 received Dec 5 16:14:40 NOTICE[10528]: rtp.c:564 ast_rtp_read: Unknown RTP codec 96 received Dec 5 16:14:40 NOTICE[10528]: rtp.c:564 ast_rtp_read: Unknown RTP codec 96 received Dec 5 16:14:40 NOTICE[10528]: rtp.c:564 ast_rtp_read: Unknown RTP codec 96 received Dec 5 16:14:40 NOTICE[10528]: rtp.c:564 ast_rtp_read: Unknown RTP codec 96 received Dec 5 16:14:40 NOTICE[10528]: rtp.c:564 ast_rtp_read: Unknown RTP codec 96 received Dec 5 16:14:40 NOTICE[10528]: rtp.c:564 ast_rtp_read: Unknown RTP codec 96 received Dec 5 16:14:40 NOTICE[10528]: rtp.c:564 ast_rtp_read: Unknown RTP codec 96 received Dec 5 16:14:40 NOTICE[10528]: rtp.c:564 ast_rtp_read: Unknown RTP codec 96 received I use the codec 711 Since I can settle this problem? Thanks in advance! Best Regards!!