Dear All, Situation (1) is SIP agent -> Asterisk TE410P -> Telcom Mobile System PRI debug Message type: (just hear about Mobile System VoiceMail IVR introduction, hangup before beep tone) Message type: SETUP (5) Message type: CALL PROCEEDING (2) Message type: ALERTING (1) Message type: DISCONNECT (69) Message type: RELEASE (77) Message type: RELEASE COMPLETE (90) GSM Mobile still not send connecting signal like following Message type: CONNECT (7) Message type: CONNECT ACKNOWLEDGE (15) but the CDR's billsec start count Situation (2) is SIP agent -> Asterisk TE410P -> Telcom Mobile System PRI debug Message type: (Realy enter VoiceMail system after beep tone) Message type: SETUP (5) Message type: CALL PROCEEDING (2) Message type: ALERTING (1) Message type: CONNECT (7) Message type: CONNECT ACKNOWLEDGE (15) Message type: DISCONNECT (69) Message type: RELEASE (77) Message type: RELEASE COMPLETE (90) My Problem is Zap Channel seems don't check PRI q.931 message type, when start billsec count or some thing I miss? Could some one help me to hack the problem? Best Regards,