ISDN Disconnect Cause Code

Hex
Code

Cause Description

Additional Information

80

Normal disconnect

The call has been disconnected normally.

81

Unallocated or
unassigned number

The ISDN number is sent to the switch in the correct format. However,
the number is not assigned to destination equipment.

82

No route to specified
network

The ISDN exchange is asked to route the call through an
unrecognized intermediate network.

The remote device has received a request to route the call through a
transit network that it does not recognize. The transit network is not
recognized because it does not exist or because it does not serve the
remote device.

This cause is supported on a network-dependent basis.

83

No route to destination

The call routes through an intermediate network that does not serve
the destination address.

This cause is supported on a network-dependent basis.

84

Send special information
tone

The remote number dialed by the user could not be reached.

The user should check the number. A prefix may be required to
access the network. For example, the user may need to dial a nine for
outbound calls through a private branch exchange (PBX). The telco or
PBX administrator can provide assistance.

85

Misdialed trunk prefix.

The remote number dialed by the user could not be reached.

The user should check the number. A prefix may be required to
access the network. For example, the user may need to dial a nine for
outbound calls through a PBX. The telco or PBX administrator can
provide assistance.

86

Channel unacceptable

The service quality of the specified channel is insufficient to accept the
connection.

The call attempt failed because the channel cannot be used.

For calls using a PBX, the user should check the PBX configuration.
For a primary rate interface (PRI), the user should check with the telco
to determine how many channels are provisioned.

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CCNP 4: Network Troubleshooting v3.0 – ISDN Disconnect Cause Code

Copyright

 2003, Cisco Systems, Inc.

Hex
Code

Cause Description

Additional Information

87

Call awarded and
delivered in established
channel

The user assigns an incoming call that is connecting to an already
established call channel.

This cause indicates that an incoming call is being connected to a
channel already in use. For example, packet-mode X.25 virtual calls.

88

Preemption

The call was blocked. The user should try the call later.

This cause may indicate that another call has a higher priority. For
example, voice calls usually have a higher priority.

If the local or remote site is connected to a PBX, the user should
check the PBX configuration. If the condition persists, the user should
contact the telco.

89

Preemption, circuit
reserved for re-use

The call was blocked. Try the call again later.

This cause may indicate that another call has a higher priority. For
example, voice calls usually have a higher priority.

If the local or remote side is connected to a PBX, the user should
check the PBX configuration. If the condition persists, the user should
contact the telco.

90

Normal call clearing

Normal call clearing occurs. No action is required.

This cause indicates that one of the users has requested that the call
be cleared. Under normal situations, the source of this cause is not the
network.

This disconnect cause code is usually the result of a failure at a higher
layer protocol. Common causes could be related to PPP,
authentication, or idle timeout issues. The user should verify the router
configuration. If the user has requested callback, then the remote
device will disconnect, generate this code, and then call the user.

91 User

busy

The called system acknowledges the connection request but cannot
accept the call because all B-channels are in use.

Note: The telco can configure multiple ISDN circuits into a hunt group.
A hunt group will switch incoming calls to the next available circuit.

92

No user responding

The connection fails because the destination does not respond to the
call.

This cause is used when a user does not respond to a call
establishment message with either an alert or a connect indication
within a period of time, which is defined in ITU-T Q.931.

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CCNP 4: Network Troubleshooting v3.0 – ISDN Disconnect Cause Code

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 2003, Cisco Systems, Inc.

Hex
Code

Cause Description

Additional Information

93

No answer from user

The destination responds to the connection request but fails to
complete the connection within the prescribed amount of time.

This cause indicates a user has provided an alerting indication but has
not provided a connect indication within a prescribed period of time.
This cause could be generated by Q.931 procedures or by internal
network timers.

The problem is at the remote end of the connection.

94

Subscriber absent

The remote device is unavailable and has been disconnected from the
ISDN network.

The user should contact the person responsible for that device.

95 Call

rejected

The destination device receives the call but rejects it for an unknown
reason.

This cause indicates that the destination device is compatible and not
busy, but does not wish to accept the call.

96

Number changed

The ISDN number used to set up the call is not assigned to a system.

This cause indicates that the number dialed is no longer assigned. An
updated number may be included in the diagnostic field. If a network
does not support this capability, cause 81 for an unassigned or
unallocated number is used.

97

Redirection to new
destination

The call is being routed to a different ISDN number.

The user should check the number dialed. The user should also verify
the PBX configuration, if applicable.

99

Exchange routing error

The call cannot be successfully routed to the remote party.

The user should check the number dialed. The user should also verify
the PBX configuration, if applicable.

9A

Non-selected user
clearing

The destination can accept the call but rejects it because it is not
assigned to the user.

9B

Destination out of order

The destination is unreachable because of an interface malfunction
and a signaling message cannot be delivered. This condition can be
temporary or last for an extended time period.

This cause indicates that a signaling message could not be delivered
to the remote user. Possible causes include physical layer or data link
layer failure at the remote user or user equipment that is off-line.

9C

Invalid number format

The connection fails because the destination address is incomplete or
presented in an unrecognizable format.

The user should verify that the format of the number dialed is correct.
This includes any appropriate digits for a PBX or long distance calls.

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CCNP 4: Network Troubleshooting v3.0 – ISDN Disconnect Cause Code

Copyright

 2003, Cisco Systems, Inc.

Hex
Code

Cause Description

Additional Information

9D

Facility rejected

The network cannot provide the facility requested by the user.

9E

Response to status
inquiry

This message is generated in response to a status inquiry message.

9F Normal,

unspecified

This message reports the occurrence of a normal event when no
standard cause applies. No action is required.

A1

Circuit out of order

The call cannot be completed because of an unspecified problem in
the ISDN network.

A2

No channel available

The connection fails because no appropriate channel is available to
take the call.

A3

Destination unattainable The destination cannot be reached through the telco network.

The user should contact the telco.

A4

Out of order

The destination cannot be reached because of a network malfunction.
This condition could last for an extended time period. An immediate
reconnect attempt will probably fail.

If the connection uses a long distance carrier, the user should try to
use a pre-subscribed inter-exchange carrier (PIC). For example, a 10-
10-xyz carrier can be used to verify that the long distance carrier is
causing the problem.

A6

Network out of order

The destination cannot be reached because of a network malfunction.
This condition can last for an extended time period. An immediate
reconnect attempt will probably fail.

If a long distance carrier is being used, the user should try using a
PIC. For example, a 10-10-xyz carrier can be used to verify that long
distance carrier is causing the problem.

A7

Permanent frame mode
connection out of service

The permanent connection was terminated. This is usually caused by
equipment failure.

The user should contact the telco if the condition persists.

A8

Permanent frame mode
connection operational

The permanent connection is fully operational again.

A9

Temporary failure

An error occurs because of a network malfunction. The problem will be
resolved shortly.

The user should contact the telco if the problem persists.

AA

Switching equipment
congestion

The destination cannot be reached because the network switching
equipment is temporarily overloaded.

The user should try again later.

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CCNP 4: Network Troubleshooting v3.0 – ISDN Disconnect Cause Code

Copyright

 2003, Cisco Systems, Inc.

Hex
Code

Cause Description

Additional Information

AB

Access information
discarded

The network cannot provide the requested access information.

This cause indicates that the network could not deliver access
information to the remote user as requested. Types of access
information include user-to-user, low layer compatibility, high layer
compatibility, or a sub-address. The diagnostic field may include the
type of access information that has been discarded.

AC

Requested channel not
available

The remote equipment cannot provide the requested channel for an
unknown reason. This can be a temporary problem.

AF

Resources unavailable,
unspecified

The requested channel or service is unavailable for an unknown
reason. This can be a temporary problem.

B1

Quality of service (QoS)
unavailable

The network cannot provide the requested quality of service. This
cause may indicate a subscription problem.

This cause reports that the QoS, which is defined in Recommendation
X.213, cannot be provided. For example, the throughput or transit
delay may not be supported.

B2

Requested facility not
subscribed

The remote equipment supports the requested supplementary service
by subscription only.

This cause indicates that the network could not provide the requested
supplementary service. The user may need to make the necessary
administrative arrangements with the supporting networks.

This error code can also be returned by the ISDN network when a call
attempt is made but the service profile identifiers (SPIDs) have not
been entered or are incorrect.

The user should ensure that the SPIDs have been entered correctly or
contact the telco to verify the SPIDs. The user should also verify that
the speed of the outgoing call, 56 kbps or 64 kbps, is supported by the
ISDN network.

B4

Outgoing calls barred

The ISDN network does not permit outgoing calls.

B5

Outgoing calls barred
within closed user group
(CUG)

The ISDN network does not permit outgoing calls.

B6

Incoming calls barred

The ISDN network does not permit incoming calls.

The user should contact the telco.

B7

Incoming calls barred
within CUG

The ISDN network does not permit incoming calls.

The user should contact the telco.

B9

Bearer capability not
authorized

The user requests a bearer capability that the network provides, but
the user is not authorized to use it. This can be caused by a
subscription problem.

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CCNP 4: Network Troubleshooting v3.0 – ISDN Disconnect Cause Code

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Hex
Code

Cause Description

Additional Information

BA

Bearer capability not
presently available

The network normally provides the requested bearer capability, but it
is currently unavailable. This can be caused by a temporary network
problem or a subscription problem.

If the incoming call is analog, such as a modem call, the user should
verify the presence of ISDN incoming voice-modem on the PRI or BRI
physical interface.

BF

Service option not
available, unspecified

The network or remote equipment cannot provide the requested
service option for an unspecified reason. This can be caused by a
subscription problem.

C1

Bearer capability not
implemented

The network cannot provide the bearer capability requested by the
user.

The user should contact the telco.

C2

Channel type not
implemented

The network or the destination equipment does not support the
requested channel type.

C5

Requested facility not
implemented

The remote equipment does not support the requested supplementary
service.

C6

Only restricted digital
information bearer
capability available

The network cannot provide unrestricted digital information bearer
capability.

This cause indicates that a device has requested an unrestricted
bearer service. The equipment sending this cause can only support
the restricted version of the requested bearer capability.

CF

Service option not
implemented,
unspecified

The network or remote equipment cannot provide the requested
service option for an unspecified reason. This can be caused by a
subscription problem.

D1

Invalid call reference
value

The remote equipment receives a call with a call reference that is not
currently in use on the user-network interface.

D2

Identified channel does
not exist

The receiving equipment has received a request to use a channel that
is not activated on the interface for calls.

For example, this cause would be generated if a user has subscribed
to Channels 1 through 12 on a PRI and the user equipment or the
network attempts to assign a call to Channels 13 through 23.

D3

Suspended call exists,
but call identity (id) does
not

The network receives a call resume request. The call resume request
contains a call identity information element that is not being used for
any suspended calls.

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CCNP 4: Network Troubleshooting v3.0 – ISDN Disconnect Cause Code

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Hex
Code

Cause Description

Additional Information

D4

Call id in use

The network receives a call resume request. The call resume request
contains a call identity information element that indicates the resume
request is for a suspended call.

This cause indicates that the network has received a call suspend
request. The call suspend request contains a call identity, which
includes the null call identity, that is already being used for a
suspended call.

D5

No call suspended

The network receives a call resume request when no suspended call
is pending. This can be a transient error that will be resolved by
successive call retries.

This cause indicates that the call resume request contains a call
identity information element that does not indicate a suspended call.

D6

Call with requested call
id has been cleared

The network receives a call resume request. The call resume request
contains a call identity information element that indicates a suspended
call. However, the suspended call was cleared by a network timeout or
by the remote user.

D7

User not member of
CUG

The call cannot be completed, probably for one of the following
reasons:

-

The user has dialed an incorrect ISDN.

-

The user is not authorized to use the requested service. The user
has not subscribed to this service.

-

The remote device is not authorized to use a service that the caller
is using.

The user should check the number dialied. If the problem persists, the
user should contact the telco.

D8

Incompatible destination An attempt is made to connect to non-ISDN equipment such as an

analog line.

This cause indicates that the remote device has received a request to
establish a call that has low layer compatibility, high layer
compatibility, or another compatibility attribute such as a data rate that
cannot be accommodated.

This code is generated when the calling device dials a non-ISDN
device. The caller should check the number dialed.

This cause could also be generated when a data call is made to voice
number or a voice call is made to a number that only supports data. If
the number is dialed correct, the telco switch may not be configured
correctly.

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CCNP 4: Network Troubleshooting v3.0 – ISDN Disconnect Cause Code

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 2003, Cisco Systems, Inc.

Hex
Code

Cause Description

Additional Information

DA

Non-existent CUG

The call cannot be completed, probably for one of the following
reasons:

-

The user has dialed an incorrect ISDN.

-

The user is not authorized to use the requested service. The user
has not subscribed to this service.

-

The remote device is not authorized to use a service that the caller
is using.

The user should check the number dialed. If the problem persists, the
user should contact the telco.

DB

Invalid transit network
selection

The ISDN exchange is asked to route the call through an
unrecognized intermediate network.

This cause indicates that the ISDN device received a transit network
identification with an incorrect format, as defined in Annex C of ITU-T
Q.931.

DF

Invalid message,
unspecified

An invalid message is received with no standard cause. This usually
results from a D-channel error.

If the error occurs systematically, the user should report it to the ISDN
service provider.

E0

Mandatory information
element missing

The receiving equipment receives a message that does not include
one of the mandatory information elements.

This cause indicates that the remote device has received a message
that cannot be processed because the message is missing a required
information element.

This cause is the result of a D-channel error. The user should ensure
that the switch type is configured correctly. A Cisco IOS® Software
upgrade on the router may help alleviate this issue. If the error occurs
systematically, the user should report it to the ISDN service provider.

E1

Message type not
implemented

The receiving equipment receives an unrecognized message. The
message is unrecognized because the message type is invalid or the
message type is valid but not supported.

This is caused by a problem with the remote configuration or with the
local D-channel.

E2

Message not compatible
with call state or not
implemented

The remote equipment receives an invalid message with no standard
cause.

This cause indicates that the remote device has received a message
that cannot be identified as a permissible message or that a status
message is received that indicates an incompatible call state.

The cause is the result of a D-channel error. If the error occurs
systematically, the user should contact the ISDN service provider.

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CCNP 4: Network Troubleshooting v3.0 – ISDN Disconnect Cause Code

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Code

Cause Description

Additional Information

E3

Information element not
implemented

The remote equipment receives a message that includes information
elements that are not recognized.

The equipment is unable to recognize the information elements
because the information element identifier is not defined or it is not
implemented by the remote equipment. However, the information
element is not required for the equipment to process the message.

This is the result of a D-channel error. If the error occurs
systematically, the user should contact the ISDN service provider.

E4

Information element
contains invalid
information

The remote equipment receives a message that includes invalid
information in the information element.

This cause indicates that the remote device has received and
implemented an information element. However, the coding in one or
more of the fields in the information element has not been
implemented by the equipment sending this cause.

This is the result of a D-channel error.

E5

Message not compatible
with call state

The remote equipment receives an expected message that does not
correspond to the current state of the connection.

This is the result of a D-channel error.

E6

Recovery on time expiry The call was not completed because an error occurred (for example a

state synchronization error.

The user should try the call later. If the problem persists, the user
should contact the ISDN service provider.

E7

Parameter not
implemented

The call was not completed because the ISDN network does not
support a service the user requires.

The user should contact the ISDN service provider.

EF

Protocol error,
unspecified

An unspecified D-channel error with no other standard cause.

FF

Interworking, unspecified An event occurs, but the network does not provide causes for the

action it takes. The precise problem is unknown.

??

Unknown cause value

The cause value is unknown.

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CCNP 4: Network Troubleshooting v3.0 – ISDN Disconnect Cause Code

Copyright

 2003, Cisco Systems, Inc.