user manual
Polycom RealPresence Collaboration Server (RMX) 1500/2000/4000 Administrator’s Guide
A-8 Polycom, Inc.
22 Number Changed Same as Cause 1. The diagnostic field contains the new 
called user number. Cause 1 is used if the network does not 
support this cause value.
26 Non-Selected User 
Clearing
The incoming call has not been assigned to the user.
27 Destination Out-of-
Order
Messages cannot be sent to the destination number because 
the span may not be active.
28 Invalid Number Format 
(address incomplete)
The Type of Number (TON) is incorrect or the number is 
incomplete. Network, Unknown and National numbers have 
different formats.
29 Facility Rejected User requested supplementary service which cannot be 
provided by the network.
30 Response to STATUS 
ENQUIRY
A STATUS message has been received in response to a prior 
STATUS ENQUIRY.
31 Normal, Unspecified A normal, unspecified disconnection has occurred.
34 No Circuit/Channel 
Available
No B-Channels are available for the call.
38 Network Out-of-Order Network is out-of-order because due to a major malfunction.
39 Permanent Frame 
Mode Connection Out-
of-Service
A permanent frame mode connection is out-of-service. This 
cause is part of a STATUS message.
40 Permanent Frame 
Mode Connection 
Operational
A permanent frame mode connection is operational. This 
cause is part of a STATUS message.
41 Temporary Failure Minor network malfunction. Initiate call again.
42 Switching Equipment 
Congestion
High traffic has congested the switching equipment. Cause 
43 is included.
43 Access Information 
Discarded
Access Information elements exceed maximum length and 
have been discarded. Included with Cause 42.
44 Requested Circuit/
Channel not Available
The requested circuit or channel is not available. Alternative 
circuits or channels are not acceptable.
47 Resource Unavailable, 
Unspecified
The resource is unavailable. No other disconnection cause 
applies.
49 Quality of Service Not 
Available
Quality of Service, as defined in Recommendation X.213, 
cannot be provided.
50 Requested Facility Not 
Subscribed
A supplementary service has been requested that the user is 
not authorized to use.
Table A-2  ISDN Disconnection Causes (Continued)
Disconnection Cause
Number Summary Description










