| 0 | No release cause |
| 1 | Unallocated (unassigned) number |
| 2 | No route to specified transit network |
| 3 | No route to destination |
| 4 | Send special information tone |
| 5 | Misdialled trunk prefix |
| 6 | Channel unacceptable |
| 7 | Call awarded and being delivered in an established channel |
| 8 | Preemption |
| 9 | Preemption - circuit reserved for reuse |
| 14 | Number ported |
| 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 | Redirection to new destination |
| 24 | Unallocated number |
| 25 | Exchange routing error |
| 26 | Non-selected user clearing |
| 27 | Destination out of order |
| 28 | Invalid number format (address incomplete) |
| 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 circuit/channel not available |
| 45 | Preemption |
| 46 | Precedence call blocked |
| 47 | Resource unavailable, unspecified |
| 49 | Quality of service not available |
| 50 | Requested facility not subscribed |
| 53 | Outgoing calls barred within CUG |
| 55 | Incoming calls beared within CUG |
| 57 | Bearer capacity not authorised |
| 58 | Bearer capacity not presently available |
| 59 | Call restriction |
| 60 | Terminal transfer rejected |
| 62 | Inconsistency in designated outgoing access information and subscriber 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 information bearer capability 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 identity call does not |
| 84 | Call identity in use |
| 85 | No call suspended |
| 86 | Call having the requested call identity card has been cleared |
| 87 | Called user not member of CUG |
| 88 | Incompatible destination |
| 90 | Non-existent CUG |
| 91 | Invalid transit network selection |
| 92 | Incorrect facility parameter |
| 95 | Invalid message, unspecified |
| 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 or not implemented |
| 99 | Information element/parameter 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 unrecognised parameter, discarded |
| 111 | Protocol error, unspecified |
| 113 | Bearer capability unavailable |
| 114 | No end-to-end information available |
| 127 | Interworking, unspecified |
| 255 | geoprobe neither rel nor rlc |