== Using SIP RTP CoS mark 5
    -- Executing [0719206651@eutelia-in:1] Answer("SIP/eutelia-00000004", "") in new stack
    -- Executing [0719206651@eutelia-in:2] Wait("SIP/eutelia-00000004", "2") in new stack
  == Redirecting 'SIP/eutelia-00000004' to fax extension due to CNG detection
  == Spawn extension (eutelia-in, fax, 1) exited non-zero on 'SIP/eutelia-00000004'
    -- Executing [fax@eutelia-in:1] Dial("SIP/eutelia-00000004", "DAHDI/11,60") in new stack
    -- Called DAHDI/11
    -- DAHDI/11-1 is ringing
    -- DAHDI/11-1 is ringing
    -- DAHDI/11-1 is ringing
    -- DAHDI/11-1 is ringing
    -- DAHDI/11-1 is ringing
    -- DAHDI/11-1 is ringing
    -- DAHDI/11-1 answered SIP/eutelia-00000004
    -- Channel 11 echo canceler disabled its NLP.
    -- Channel 11 detected a CED tone from the network.
  == Using UDPTL CoS mark 5
[Apr  9 21:21:59] NOTICE[1673]: channel.c:4152 __ast_read: Dropping incompatible voice frame on DAHDI/11-1 of format slin since our native format has changed to 0x8 (alaw)
[Apr  9 21:21:59] ERROR[1673]: astobj2.c:110 INTERNAL_OBJ: user_data is NULL
    -- Hanging up on 'DAHDI/11-1'
    -- Hungup 'DAHDI/11-1'
  == Spawn extension (eutelia-in, fax, 1) exited non-zero on 'SIP/eutelia-00000004'