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MERLIN LEGEND Communications System Release 6.1
Network Reference
555-661-150
Issue 1
August 1998
Glossary
Page GL-27
U
trunk Telecommunications path between the communications
system and the telephone company central office (
CO
) or
another switch. Often used synonymously with
line
.
trunk jack See
line/trunk jack
.
trunk pool See
pool
.
TSAPI Telephony Services Application Programming Interface.
An application programming interface that allows computer
telephony applications to be used. TSAPI is supported by
the MERLIN LEGEND Communications System Release
5.0.
See also TAPI, CTI.
TTR (touch-tone receiver) Device used to decode
DTMF
touch-
tones dialed from
single-line
or
Remote Access
telephones.
UDP (Uniform Dial Plan) Composed of the
local dial plan
and
non-local dial plan
. A dial plan that allows a caller at any
extension in a
private network
to dial the same number of
digits to reach any other extension in the private network,
even if the originating extension is physically connected to
one communications system and the terminating extension
is physically connected to a different communications
system.
unambiguous
numbering
The practice of numbering of extension ranges, remote
access codes, or other system components to avoid routing
conflicts in network or local calling. For example, Extension
441 is unique when compared to Extension 4410. However
it is ambiguous, because a system routes as soon as it
matches the digits sent for a call with the digits in a local
plan or in a non-local dial plan extension range. When a
caller dials
4410, a system routes the call to Extension 441
immediately, without considering the last dialed digit.
Uniform Dial Plan See
UDP
.
uninterruptible
power supply
See
UPS
.
unit load Measure of the power load drain of a module, telephone, or
adjunct
.
unmonitored
extension
An extension for which no CTI application is receiving call
information. See also
CTI link
and
monitored extension
.
unrestricted data
channel
Unrestricted data channels (also called clear data
channels) allow the transmission of occurrences of more
than seven contiguous zero bits. If an unrestricted data
channel is requested and only restricted channels are
available, the call will be rejected. See also restricted data
channel.