ISDN User Part - Release Codes

Release Codes

Release codes are used to identify and debug any events occurring in ISDN User Part signaling. Every event in ISUP signaling generates a release code number. Even for a normal ISUP call, a release code is generated. There are lot of applications developed based on the release code from ISUP signaling. Similarly Telecom operators trace for Release codes to debug any call failures.

Following are the list of releases codes used. Release codes only defined by number are effectively undefined, and may be used for proprietary solutions.

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
10. 10
11. 11
12. 12
13. 13
14. 14
15. 15
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
32. 32
33. 33
34. No circuit/channel available
35. 35
36. 36
37. 37
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
48. 48
49. Quality of service unavailable
50. Requested facility not subscribed
51. Call type incompatible with service request (ANSI)
52. 52
53. Outgoing calls barred within CUG
54. Call blocked due to group restrictions (ANSI)
55. Incoming calls barred within CUG
56. 56
57. Bearer capability not authorized
58. Bearer capability not presently available
59. 59
60. 60
61. 61
62. Inconsistency in designed outg. access inf. and subscr. class
63. Service or option not available, unspecified
64. 64
65. Bearer capability not implemented
66. Channel type not implemented
67. 67
68. 68
69. Requested facility not implemented
70. Only restricted digital bearer cap. is available
71. 71
72. 72
73. 73
74. 74
75. 75
76. 76
77. 77
78. 78
79. Service or option not implemented, unspecified
80. 80
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
89. 89
90. Non-existing CUG
91. Invalid transit network selection
92. 92
93. 93
94. 94
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
104. 104
105. 105
106. 106
107. 107
108. 108
109. 109
110. Message with unrecognized parameter discarded
111. Protocol error, unspecified
112. 112
113. 113
114. 114
115. 115
116. 116
117. 117
118. 118
119. 119
120. 120
121. 121
122. 122
123. 123
124. 124
125. 125
126. 126
127. Interworking, unspecified