[a2billing]
exten => _X.,1,Answer
exten => _X.,n,AGI(a2billing.php,1)
exten => _X.,n,Hangup

  == Using SIP RTP CoS mark 5
    -- Executing [9@net2speak:1] Goto("SIP/1030-0000000d", "a2billing,9999,1") in new stack
    -- Goto (a2billing,9999,1)
    -- Executing [9999@a2billing:1] Answer("SIP/1030-0000000d", "") in new stack
    -- Executing [9999@a2billing:2] AGI("SIP/1030-0000000d", "a2billing.php,1") in new stack
    -- Launched AGI Script /var/lib/asterisk/agi-bin/a2billing.php
<SIP/1030-0000000d>AGI Tx >> agi_request: a2billing.php
<SIP/1030-0000000d>AGI Tx >> agi_channel: SIP/1030-0000000d
<SIP/1030-0000000d>AGI Tx >> agi_language: en
<SIP/1030-0000000d>AGI Tx >> agi_type: SIP
<SIP/1030-0000000d>AGI Tx >> agi_uniqueid: 1384258569.13
<SIP/1030-0000000d>AGI Tx >> agi_version: 1.8.15-cert3
<SIP/1030-0000000d>AGI Tx >> agi_callerid: 1030
<SIP/1030-0000000d>AGI Tx >> agi_calleridname: Salman Office
<SIP/1030-0000000d>AGI Tx >> agi_callingpres: 0
<SIP/1030-0000000d>AGI Tx >> agi_callingani2: 0
<SIP/1030-0000000d>AGI Tx >> agi_callington: 0
<SIP/1030-0000000d>AGI Tx >> agi_callingtns: 0
<SIP/1030-0000000d>AGI Tx >> agi_dnid: 9
<SIP/1030-0000000d>AGI Tx >> agi_rdnis: unknown
<SIP/1030-0000000d>AGI Tx >> agi_context: a2billing
<SIP/1030-0000000d>AGI Tx >> agi_extension: 9999
<SIP/1030-0000000d>AGI Tx >> agi_priority: 2
<SIP/1030-0000000d>AGI Tx >> agi_enhanced: 0.0
<SIP/1030-0000000d>AGI Tx >> agi_accountcode:
<SIP/1030-0000000d>AGI Tx >> agi_threadid: -1237877904
<SIP/1030-0000000d>AGI Tx >> agi_arg_1: 1
<SIP/1030-0000000d>AGI Tx >>
    -- <SIP/1030-0000000d>AGI Script a2billing.php completed, returning 0
    -- Executing [9999@a2billing:3] Hangup("SIP/1030-0000000d", "") in new stack
  == Spawn extension (a2billing, 9999, 3) exited non-zero on 'SIP/1030-0000000d'