DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4
June 1999
Maintenance Architecture
1-36Protocols
1
This is because, through messaging , the terminating node knows the orig inating
node cannot provid e disconnect sup ervision. This messaging is not possib le with
non-DCS tie trunks, and the direct c all is denied.
Some two-wire loop start trunks outside the United States provide busy tone
disconnect in p lace of line signals. For these trunks, an adjunc t can be attached
to the trunk to listen for busy or other disc onnect tone. When a tone is detected ,
the adjunct sends line s ignals for disconnec t to the system.
Administration is provided for each trunk group to ind icate whether it provides
disconnect sup ervision for incoming ca lls and for outgoing c alls.
Transfer on Ringing
A station or attendant may conferenc e in a ringing station or transfer a p arty to a
ringing station. When a station conferenc es in a ringing station and t hen drops
the call, the ringing stati on is treated like a party without disc onnect supervision.
However, when a station transfers a party to a ring ing station, the ringing stati on
party is treated like a par ty with disconnect sup ervision. Two timers (Attendant
Return Call Timer and Wait Answer Supervision Timer) are provided to ensure the
call is not locked to a ring ing station.
Conference, Transfer, and Call-Forwarding Denial
If a station or attendant attempts to c onnect parties without d isconnect
supervision together, the following is possible:
■

Digital Station or Local Attendant Transfer

: if a digital station attemp ts to
transfer the two parties together, the c all appearance lamp flutters,
indicating a d enial. If transferring to a DCS trunk, the denial may drop th e
call since the transfer is allowed and the other system is queried f or
disconnect sup ervision.
■

Analog Station Transfer

: if an analog station attempts to transfer two
parties together by g oing on-hook, the analog station is no lon ger on the
call and the transfer cannot b e denied.
■

Centralized Attendant Service (CA S) Attendant Transfer

: if a CAS attempts
to transfer two parties together b y pressing the release key, the release
link trunk is released and the branc h attempts a transfer by goi ng on-hook
■

Station Conference/Dropout

: if a station conferences all p arties, the
conference is allowed sinc e the station has disconnect sup ervision. When
the station is dropped from the call, the call is drop ped since the other
parties do not have disconnect supervision.
■

Station Call Forwarding

: if a station is call forwarded off-premise to a trunk
without disconnect sup ervision, the calling pa rty without disconnect
supervision is routed to the attend ant
Table 1-11 lists the various protocols, with ap plications and maximum limitations.