Netopia 435 Reference Manual page 248

ISDN Events E-5
Cause No. 22: number changed. This cause is returned to a calling
user when the called party number indicated by the calling user is
no longer assigned. The new called party number may optionally be
included in the diagnostic field. If a network does not support this
capability, cause No. 1, unassigned (unallocated) number, shall be
used.
Cause No. 26: non-selected user clearing. This cause indicates
that the user has not been awarded the incoming call.
Cause No. 27: destination out of order. This cause indicates that
the destination indicated by the user cannot be reached because
the interface to the destination is not functioning correctly. The term
"not functioning correctly" indicates that a signaling message was
unable to be delivered to the remote user: e.g., a physical layer or
data link layer failure at the remote user, user equipment off-line,
etc.
Cause No. 28: invalid number format (address incomplete). This
cause indicates that the called user cannot be reached because the
called party number is not a valid format or is not complete.
Cause No. 29: facility rejected. This cause is returned when a
facility requested by the user cannot be provided by the network.
Cause No. 30: response to STATUS INQUIRY. This cause is
included in the STATUS message when the reason for generated the
STATUS message was the prior receive of a STATUS INQUIRY
message.
Cause No. 31: normal, unspecified. This cause is used to report a
normal even only when no other cause in the normal class applies.
Cause No. 34: no circuit/channel available. This cause indicates
that there is no appropriate circuit/channel presently available to
handle the call.
Cause No. 38: network out of order. This cause indicates that the
network is not functioning correctly and that the condition is likely to
last a relatively long period of time: e.g., immediately reattempting
the call is not likely to be successful.