Number,Cause,Reference 1,Unassigned/unallocated number,[RFC5457] 2,No route to specified transit network,[RFC5457] 3,No route to specified transit network,[RFC5457] 4-5,Unassigned, 6,Channel unacceptable,[RFC5457] 7,Call awarded and delivered,[RFC5457] 8-15,Unassigned, 16,Normal call clearing,[RFC5457] 17,User busy,[RFC5457] 18,No user response,[RFC5457] 19,No answer,[RFC5457] 20,Unassigned, 21,Call rejected,[RFC5457] 22,Number changed,[RFC5457] 23-26,Unassigned, 27,Destination out of order,[RFC5457] 28,Invalid number format/incomplete number,[RFC5457] 29,Facility rejected,[RFC5457] 30,Response to status enquiry,[RFC5457] 31,"Normal, unspecified",[RFC5457] 32-33,Unassigned, 34,No circuit/channel available,[RFC5457] 35-37,Unassigned, 38,Network out of order,[RFC5457] 39-40,Unassigned, 41,Temporary failure,[RFC5457] 42,Switch congestion,[RFC5457] 43,Access information discarded,[RFC5457] 44,Requested channel not available,[RFC5457] 45,Pre-empted (causes.h only),[RFC5457] 46,Unassigned, 47,"Resource unavailable, unspecified (Q.931 only)",[RFC5457] 48-49,Unassigned, 50,Facility not subscribed (causes.h only),[RFC5457] 51,Unassigned, 52,Outgoing call barred (causes.h only),[RFC5457] 53,Unassigned, 54,Incoming call barred (causes.h only),[RFC5457] 55-56,Unassigned, 57,Bearer capability not authorized,[RFC5457] 58,Bearer capability not available,[RFC5457] 59-62,Unassigned, 63,Service or option not available (Q.931 only),[RFC5457] 64,Unassigned, 65,Bearer capability not implemented,[RFC5457] 66,Channel type not implemented,[RFC5457] 67-68,Unassigned, 69,Facility not implemented,[RFC5457] 70,Only restricted digital information bearer capability is available (Q.931 only),[RFC5457] 71-78,Unassigned, 79,Service or option not available (Q.931 only),[RFC5457] 80,Unassigned, 81,Invalid call reference,[RFC5457] 82,Identified channel does not exist (Q.931 only),[RFC5457] 83,"A suspended call exists, but this call identity does not (Q.931 only)",[RFC5457] 84,Call identity in use (Q.931 only),[RFC5457] 85,No call suspended (Q.931 only),[RFC5457] 86,Call has been cleared (Q.931 only),[RFC5457] 87,Unassigned, 88,Incompatible destination,[RFC5457] 89-90,Unassigned, 91,Invalid transit network selection (Q.931 only),[RFC5457] 92-94,Unassigned, 95,"Invalid message, unspecified",[RFC5457] 96,Mandatory information element missing (Q.931 only),[RFC5457] 97,Message type nonexistent/not implemented,[RFC5457] 98,Message not compatible with call state,[RFC5457] 99,Information element nonexistent,[RFC5457] 100,Invalid information element contents,[RFC5457] 101,Message not compatible with call state,[RFC5457] 102,Recovery on timer expiration,[RFC5457] 103,Mandatory information element length error (causes.h only),[RFC5457] 104-110,Unassigned, 111,"Protocol error, unspecified",[RFC5457] 112-126,Unassigned, 127,"Internetworking, unspecified",[RFC5457] 128-255,Unassigned,