Indicates the codes for the cause of a disconnect. Cause Values: For each class, the description of its cause value is given. Note that the value corresponds to the decimal value of the 7 least significant bits since the bit 8 is always set to 1. Class 000, Normal Events: 1 Unassigned number 2 No route to specified transit network 3 No route to destination 6 Channel unacceptable 7 Call awarded and deliivered in an established channel 16 Normal call clearing 17 User busy 18 No user responding 19 User alerting, no answer 21 Call rejected 22 Number changed 26 Non-selected user clearing 27 Destination out of order 28 Invalid number format (incompatible number) 29 Facility rejected 30 Response to STATUS ENQUIRY 31 Normal unspecified Class 010, Network Congestion: 34 No circuit/channel available 38 Network out of order 41 Temporary failure 42 Switching equipment congestion 43 User info discarded 44 Requested channel not available 47 Resources unavailable - unspecified Class 011, Service or Option Not Available: 49 Quality of service unavailable 50 Requested facility not subscribed 57 Bearer capability not authorized 58 Bearer capability not presently authorized 63 Service or option not available, unspecified or Option Not Implemented: 65 Bearer capability not implemented 66 Channel type not implemented 69 Requested facility not implemented 70 Only restricted digital information bearer capability is available 79 Service or option not implemented, unspecified Class 101, Invalid Message: 81 Invalid call reference value 82 Identified channel does not exist 83 Suspended call exits, but this call identity does not 84 Call identity in use 85 No call suspended 86 Call having the requested call identity has been cleared 88 Incompatible destination 91 Invalid transit network selection 95 Invalid message, unspecified Class 110, Protocol Error: 96 Mandatory information element is missing 97 Message type non-existent or not implemented 98 Message not compatible with call state or message type non-existent of not implemented 99 Information element non-existent or not implemented 100 Invalid information element contents 101 Message not compatible with call state 102 Recovery on time expiry 111 Protocol error, unspecified Class 111, Interworking: 127 Interworking, unspecified Range of Values: 0-127 Default Value: none