ISDN Disconnection Cause

This source of this ISDN cause is from ETS 300 102-1 Annex G. You can download the complete ETS 300 102-1 standard, the layer 3 basic call control, from the site

Normal Class

Code Disconnection Cause 
1 Unallocated
2 No route to specified transit network
3 No route to destination 
6 Channel unacceptable
7 Call awarded and being delivered in an established channel
16 Nomal call clearing
17 User busy
18 No user responding
19 No answer from user (user alerted)
21 Call rejected
22 Number changed
27 Destination out of order
28 Invalid formate (address incomplete)
29 Facility rejected
30 Response to status enquiry
31 Normal, unspecified

Resource Unavailable Class

34 No circuit/channel available
38 Network out of order
41 Temporary failure
42 Switching equipment congestion
43 Access information discarded
44 Request circuit/channel not available
47 Resource unavailable, unspecified

Service or Option not Available Class

49 Quality of service not available
50 Requested facility not subscribed
57 Bearer capability not authorized
58 Bearer capability not presently available
63 Serice or option not available, unspecified

Service or Option not Implemented Class

65 Bearer capability not implemented
66 Channel type not implemented
69 Requested facility not implemented
70 Only restricted digital information bearer capability is unavailable
79 Service option not implemented, unspecified

Invalid Message (e.g., parameter out of range) Class

81 Invalid call reference value
82 Identified channel does not exist
83 A suspended call exist, but this call identify 
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

Protocol Error (e.g., unknown message) Class

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 non-existent or not implemented
100 Invliad information element contents
101 Message not compatible with call state
102 Recovery on timer expiry
111 Protocol error, unspecified

Interworking Class

127 Interworking unspecified

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