NEC NDA-24305 - page 270

CHAPTER 6 NDA-24305
Page 25 2
Revision 1.0
CALL COMPLETION TO BUSY SUBSCRIBER (CCBS)
(c) If the fault occurs when informing the calling station that the called station becomes idle, CCBS is
canceled at the side of station to be s et , b ut n ot ca nceled at the s ide of c alli ng st ation s ince the m essage
is not sent to the station.
(d) If the fault occurs when the calling station answers the recall (CCBS call), CC BS is canceled at the
side of the calling station but not canceled at t he side of the called station since the message is not se nt
to the station.
20. The c onditions of alternate routing are as follows.
(a) If the data link fault occurs when the station is operating to set CCBS, the message for service set is
sent using alternate route providin g t ha t t h e i n terface i s Q -SIG/IS-11572.
(b) The same route is used for sending service set message and recall (the other route cannot be used).
Therefore, recall is not completed si nce all trunks ( B-channel ) of the corre sponding r out e are b us y, the
system processes the call as follows.
• All B-channel trunks at the system of an calling station are busy:
cancel CCBS and send the busy tone to the calling station.
• All B-channel trunks at the mediate system are busy :
send the message of CCBS recall fault to the calling station and the message of CCBS cancel to the
called station.
21. The description below are interactions between CCBS and Call Forwarding service (All Calls, Busy Line,
Don’t Answer).
(a) When setting CCBS to the station which is set C.F . service , the time of se tting CCBS decides whet her
the service is set or not.
Note 1: When the calling station recalls the station which is set CCBS service after answering CCBS recall, No
Answer Timer time out is effective. If the timer expires, the recall is forwarded to the destination.
Note 2: The station to b e set CCBS is not changed after CCBS ser v ice set even if C.F. - Don’t A nswer serv i c e
is canceled.
(b) When Call Forwarding - All Calls/Busy Line/Don’t Answer is set on a calling station, the system
recalls the ca lling party.
(c) When a called station is set Call Forwarding - All Calls/Busy Line/Don’t Answer after CCBS service
is set to the station, a calling station recalls the called station (forwarding station). As for a called
station to be set Call Forwarding - Don’t Answer, the destination station is recalled from the calling
station if No Answer Timer expires.
4. Programming
Assign the basic data for establishing the Q-SIG or the IS-11572 (since Series 7400 software) line referring to
“IS-11572 (Layer 3 specifications for inter-PBX signaling protocol)” or “Q-SIG Circuit Switched Basic Call-
ETSI Version ” in this cha pter.
C.F. - Al l Calls C.F. - Busy Line C.F. - Do n’t Answ er
C.F. is incomplete
C.F. is not ap plicable (th e condition
for making C.F. complete is not agreed)
(before) C.F. is activated
- - CCBS is set to the forward-
ing station (called station)
Note 1, Note 2
(after) C.F. is complete Not Available Not Available -