SVC cause number. The index will be 0.0 and should be disregarded. The following cause numbers maybe returned by stdx: 1 - unassigned number, callee is not assigned 2 - no route to specified transit network 3 - no route to destination 6 - channel unacceptable 16 - normal clearing 17 - user busy 18 - no user responding 21 - call rejected by whoever is sending this cause 22 - number changed, called party has changed its number 27 - destination out of order (the interface to called user) 28 - called party number is invalid 29 - facility requested can't be provided by network 30 - included in STATUS message to indicate it is responding to a STATUS ENQUIRY 31 - unspecified, used if no other cause is appropriate 34 - no circuit or channel available to handle the call 38 - network is out of order 41 - tempprary failure, i.e., caller may try again 42 - network congestion 43 - access information (user-to-user) discarded 44 - requested circuit unavailable 58 - bearer capability not available 63 - requested service unavailable 65 - requested bearer capability is not implemented 81 - call reference is unknown 95 - invalid message 96 - mandatory information element is missing 97 - message type is unknown 98 - message not compatible with call state 99 - information element is unknown or not implemented 100 - invalid information element contents 101 - message not compatible with call state