NEC Visualink 128/384 Engineering Guide

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VisuaLink 128/384 Engineering Guide Appendix C
Appendix C:  ISDN Q.931 Cause Code Definitions
The following table defines the Q.931 cause codes that the VisuaLink 128/384 
writes to event files.  Q.931 specification defines the layer-3 protocol for two 
connected ISDN devices.
Table C:  ISDN Q.931 Cause Code Definitions
CodeMeaningExplanation
1Unallocated (unassigned) numberThe requested destination can not be reached because the number 
is not currently assigned.
2No route to specified transit networkThe route to the destination network is not recognized, either 
because it does not exist or because it does not serve the equipment 
sending the message.
3No route to destinationThe network through which the call has been routed does not serve 
the desired destination.
8PreemptionA call is being cleared because the B-channel is being preempted for 
a call of higher priority.  If the preempted B-channel is not needed for 
the preempted call, it is released for prior use.
9Preempted - circuit reserved for reuseA call is being cleared because the B-channel is being preempted for 
a call of higher priority.  The B-channel is dedicated to the preempted 
call.
16Normal call clearingA call is being cleared at the request of one of the users.
17User busyThe user line is busy.
18No user respondingNo alert or connect indication was received within the prescribed 
period of time.
19No answer from user (user alerted)Connection has not been established in the specified time period, 
and an alert has been received.  (Internal network timers may 
generate this cause.)
21Call rejectedThe call was rejected despite the equipment being compatible and 
not in use.
22Number changedThe number of the called party is no longer assigned: the new 
number may be reported in the message.  Cause code 1 is assigned 
if the network does not support this function.
27Destination out of orderA signaling message could not be delivered to the user, indicating 
that the interface to the destination is not functioning correctly.
28Invalid number format (address 
incomplete)The user cannot be reached because the number is incomplete or in 
the wrong format.
30Response to STATUS ENQUIRYA message has been received in response to a STATUS ENQUIRY.
31Normal, unspecifiedA normal event has occurred for which no other cause applies.
34No circuit/channel availableNo appropriate circuit or channel is currently available to handle the 
call.
41Temporary failureThe network is temporarily not functioning correctly.
42Switching equipment congestionThe switching equipment is experiencing a period of high traffic. 
						

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Appendix C VisuaLink 128/384 Engineering Guide
43Access information discardedThe network could not deliver access information; the type of 
information discarded - for example, sub-address or protocol - may 
be provided in the message.
44Requested circuit/channel not availableThe requested circuit or channel is not available.
47Resource unavailable, unspecifiedA resource is unavailable, and no other cause code applies.
50Requested facility not subscribedThe user has not subscribed to the requested service.
52Outgoing calls barredThe caller is not authorized to make calls.
54Incoming calls barredThe recipient has rejected the call.
57Bearer capability not authorizedThe user is not authorized to use the requested capability.
58Bearer capability not presently availableThe requested capability is not currently available.
65Bearer capability not implementedThe equipment does not support the requested capability.
66Channel type not implementedThe equipment does not support the requested channel type.
69requested facility not implementedThe equipment does not support the requested supplemental 
service.
70Only restricted digital information bearer 
capability is availableThe equipment supports only the restricted version of a service 
capability.
79Service or option not implemented, 
unspecifiedThe service or option is not implemented, and no other cause code 
applies.
81Invalid call reference valueThe call reference value does not match an existing call.
82Identified channel does not existThe requested channel can not be assigned to the call - for example, 
channel 13 through 23 have been requested, and the user has 
subscribed only to channels 1 through 12.
83A suspended call exists, but this call 
identify does notThe requested call can not be resumed because it does not 
correspond to a suspended call.
88Incompatible destinationThe requested call can not be accommodated because of protocol 
differences or other incompatibilities, such as data rate.
96Mandatory information element is missingThe call can not be completed because a mandatory information 
element is missing.
97Message type non-existent or not 
implementedThe received message is not a recognized message type.
98Message not compatible with call state, or 
message type non-existent or not 
implementedThe message can not be received while in the call state.
100Invalid information element contentsInformation received could not be processed because of incorrectly 
coded elements.
101Message not compatible with call stateThe message received is not compatible with the call state.
102Recovery on time expiryA recovery procedure has been initiated after the prescribed time.
127Interworking, unspecifiedThe message was triggered by internetworking with a network that 
does not provide cause codes.
Table C:  ISDN Q.931 Cause Code Definitions
CodeMeaningExplanation 
						

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VisuaLink 128/384 Engineering Guide Appendix C
901No response from the remote terminalAutomatic dialer has timed out.  Please check number and try again.
903Network failureLayer 1 failure.  Verify physical network connection.
904Network failureLayer 2 failure.  Verify the pin out between the CODEC and the 
network termination device is correct.
905Network Failure or wrong contactTEI error.  If failure continues contact your carrier.
906Network ContactLayer 3 (caller timer timed out).  Try again.
907Disconnected by initializationNegotiation between switch and CODEC has failed.  Power the unit 
off and on again.
908Disconnected by initializationNegotiation between switch and CODEC has failed.  Power the unit 
off and on again.
912Disconnected by initializationSoftware processing other task.  Power the unit off and on again.
913Disconnected by initializationSoftware processing other task.  Power the unit off and on again.
914Network failureLower layer negation has failed.  Try again.  If problem continues 
contact your carrier.
915Network failureLower layer negation has failed.  Try again.  If problem continues 
contact your carrier.
916The provisioned communication timer 
expiredCall condition is No Good.  Please check number and try again.
917Running Network Initialize ProcedureLayer 3 initialization has not completed.  Wait a few minutes and try 
again.
918Incorrect registered SPID numbersCheck SPID registration.
919A connection could not be madeCES pointing error.  Wait a few seconds and try again.  If problem 
continues contact your carrier.
980DisconnectedVCE (Video Chip has hung up).  Reset the unit and try again.
Table C:  ISDN Q.931 Cause Code Definitions
CodeMeaningExplanation 
						

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Appendix C VisuaLink 128/384 Engineering Guide
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