Title: ISUP Release Codes
Source: http://en.wikipedia.org/wiki/ISDN_User_Part
Date: 2013-02-05


1: Unallocated (unassigned) number
2: No route to specific transit network
3: No route to destination
4: Send special info tone
5: Misdialed trunk prefix
6: Channel unacceptable
7: Call awarded and being delivered in established channel
8: Preemption
9: Preemption – circuit reserved for reuse
16: Normal call clearing
17: User busy
18: No user responding
19: No answer from user (user alerted)
20: Subscriber absent
21: Call rejected
22: Number changed
23: Redirect to new destination (unallocated destination number ANSI)
24: Unknown business group (ANSI)
25: Exchange routing error (ANSI)
26: Non-selected user clearing
27: Destination out of order
28: Invalid number format
29: Facility rejected
30: Response to STATUS ENQUIRY
31: Normal, unspecified
34: No circuit/channel available
38: Network out of order
39: Permanent frame mode connection out of service
40: Permanent frame mode connection operational
41: Temporary failure
42: Switching equipment congestion
43: Access information discarded
44: Requested channel/circuit not available
45: Preemption (ANSI)
46: Precedence call blocked
47: Resources unavailable, unspecified
49: Quality of service unavailable
50: Requested facility not subscribed
51: Call type incompatible with service request (ANSI)
53: Outgoing calls barred within CUG
54: Call blocked due to group restrictions (ANSI)
55: Incoming calls barred within CUG
57: Bearer capability not authorized
58: Bearer capability not presently available
62: Inconsistency in designed outg. access inf. and subscr. class
63: Service or option not available, unspecified
65: Bearer capability not implemented
66: Channel type not implemented
69: Requested facility not implemented
70: Only restricted digital bearer cap. is available
79: Service or option not implemented, unspecified
81: Invalid call reference value
82: Identified channel does not exist
83: A suspended call exists, 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
87: User not member of CUG
88: Incompatible destination
90: Non-existing CUG
91: Invalid transit network selection
95: Invalid message, unspecified
96: Mandatory information element is missing
97: Message type non-existing or not implemented
98: Message incompatible with call state or mesg type non-existent or 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 timer expiry
103: Parameter non-existent or not implemented - passed on
110: Message with unrecognized parameter discarded
111: Protocol error, unspecified
127: Interworking, unspecified
