Instruction manual

Tools that restrict unauthorized outgoing calls
Issue 9 May 2003
5-23
Trunk-to-trunk transfer
Trunk-to-trunk transfer allows a station to connect an incoming trunk to an
outgoing trunk and then drop the connection. When this feature is disabled, it
prevents stations from transferring an incoming trunk call to an outgoing trunk.
Then if the controlling station drops off the call, the call is torn down.
NOTE:
Hackers use this to convince unsuspecting employees to transfer them to 9#
or 900. If trunk-to-trunk transfer is allowed, the station can transfer the
incoming trunk call to an outgoing trunk and hang up, leaving the trunks still
connected.
System 75, System 85, Communication Manager, MultiVantage™ Software,
DEFINITY ECS, DEFINITY G1, G2, G3V1, and G3V2 can either allow or disallow
trunk-to-trunk transfer. This is for public network trunks only. DS1 and WATS
trunks assigned as tielines are not considered public network trunks.
DEFINITY G3V3 and later releases, including DEFINITY ECS Release 5 and
later, offer three options:
■ all — All trunks are transferred.
■ restricted — Public network trunks are not transferred.
■ none — No trunks are transferred.
NOTE:
Starting with DEFINITY ECS Release 5, trunk-to-trunk transfer is
automatically restricted via administration. To this end, the
Restriction
Override
field in the Class of Restriction screen is set to none by default.
To disallow this feature, refer to the procedure provided in ‘‘Disallow trunk-to-trunk
transfer’’ on page 5-43.
NOTE:
When conferencing calls, to prevent inadvertent trunk-to-trunk transfers,
always conference together two outgoing calls. When the calling station
disconnects, it forces the trunks to disconnect as well.
NOTE:
When the trunk-to-trunk transfer feature is disabled, the attendant console
can continue to pass dial-tone to an inbound trunk caller by pressing
Start 9
Release
.