Polycom VSX Series - Manual (Page 219)

Appendix
Appendix - 15
127 Interworking,
unspecified An event occurred within a network that does not
provide causes for the action that it takes. The
precise problem is unknown.
145 ISDN layer 1 and/or
2 link not
established User needs to check cabling, ISDN adapter status
and network connections.
146 ISDN layer 3
connection to the
ISDN
switch/network
inactive There is either a switch protocol error, or (in the
United States or Canada) a SPID assignment
problem.
255 ISDN command
processing error The ISDN signaling code has encountered an
error processing an ISDN action. ISDN adapter
busy-wait and retry.
Code Cause Definition