Cause Codes (ISDN)

When a call on a ISDN digital trunk ends, a cause code is shown in the Monitor trace. This is not necessarily an error as cause codes are shown at the end of normal calls.

The list below covers the most common cause codes seen:

  • 1 - Unallocated (unassigned) number.

  • 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 - Normal call clearing.

  • 17 - User busy.

  • 18 - No user responding

  • 19 - No answer from user (user alerted).

  • 21 - Call Rejected.

  • 22 - Number changed.

  • 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.

  • 41 - Temporary failure.

  • 42 - Switching equipment congestion.

  • 43 - Access information discarded.

  • 44 - Requested circuit/channel not available.

  • 47 - Resources unavailable, unspecified.

  • 49 - Quality of service unavailable.

  • 50 - Requested facility not subscribed.

  • 57 - Bearer capability not authorized.

 

  • 58 - Bearer capability not presently available.

  • 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 call identity does not.

  • 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.  

  • 96 - Mandatory information element is missing.

  • 97 - Message type nonexistent or not implemented.

  • 98 - Message not compatible with call state or message type nonexistent or not implemented.

  • 99 - Information element nonexistent or not implemented.

  • 100 - Invalid information element contents.

  • 101 - Message not compatible with call state.

  • 102 - Recovery on timer expiry.

  • 111 - Protocol error, unspecified.

  • 127 - Interworking, unspecified.