Netopia Router PN Series - Manual (Page 262)

D-4 Reference Guide
Cause No. 2: no route to specified transit network. This cause
indicates that the equipment sending this cause has received a
request to route the call through a particular transit network which it
does not recognize. The equipment sending this cause does not
recognize the transit network either because the transit network
does not exist or because that particular network, while it does
exist, does not serve the equipment that is sending this cause.
This cause is supported on a network-dependent basis.
Cause No. 3: no route to destination. This cause indicates that
the called user cannot be reached because the network through
which the call has been routed does not serve the destination
desired.
This cause is supported on a network-dependent basis.
Cause No. 6: channel unacceptable. This cause indicates that the
channel used in this call is not acceptable to the sending entity.
Cause No.7: call awarded and being delivered in an established
channel. This cause indicates that the user is receiving an incoming
call, which is being connected to a channel already used by that
user for similar calls (e.g., packet-mode X.25 virtual calls).
Cause No. 16: normal call clearing. This cause indicates that the
call is being cleared because one of the users involved in the call
has requested that the call be cleared.
Under normal situations, the source of this cause is not the
network.
Cause No. 17: user busy. This cause is used when the called user
has indicated the inability to accept another call.
It is noted that the user equipment is compatible with call.
Cause No. 18: no user responding. This cause is used when a
user does not respond to a call establishment message with either
an alerting or connect indication within the prescribed period of time
allocated (defined in Recommendation Q.931 by the expiry of either
timer T303 or T310).
Cause No. 19: no answer from user (user alerted). This cause is
used when a user has provided an alerting indication but has not
provided a connect indication within a prescribed period of time.