Q.850 Cause Codes - Polycom VSX 3000 Administrator's Manual

Administrator's Guide for the VSX Series

Q.850 Cause Codes

Appendix - 6
The following table describes codes that the ISDN switch sends to the VSX
system to indicate call status. Although the codes are standardized, each ISDN
service provider defines them differently. Because of this, the definitions in the
table may not exactly match the messages that you see.
Code Cause
1 Unassigned number
2 No route to specified
transit network
3 No route to
destination
6 Channel
unacceptable
7 Call awarded and
delivered
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
Definition
The switch received the sent ISDN number in the
correct format, but no destination equipment uses
the number.
The ISDN exchange does not recognize the
intermediate network through which to route the
call.
The intermediate network through which the call is
routed does not serve the destination address.
The specified channel does not provide adequate
service quality to accept the requested
connection.
The user is assigned an incoming call that is being
connected to a call channel that has already been
established for this user and this type of call.
The originator or receiver of the call has requested
that it be cleared.
All B channels are in use; the called system
acknowledges the connection request, but is
unable to accept the call.
The destination equipment does not respond to
the call, so the connection cannot be completed.
The destination equipment did not complete the
connection within the prescribed time after
responding to the connection request. The
problem is at the remote end of the connection.
The destination equipment is capable of accepting
the call, but has rejected it for an unknown reason.
The ISDN number used to set up the call is no
longer valid. (The diagnostic field of the message
may return an alternate address assigned to the
called equipment.)
The destination is capable of accepting the call,
but did not assign it to the user.