AT&T MERLIN LEGEND Installation & Maintenance Manual page 694

Glossary
digital
The representation of
information in discrete
elements such as off and on
or 0 and 1. See also analog
transmission.
Digital Communications
Protocol (DCP)
An AT&T proprietary protocol
used to transmit both
digitized voice and data over
the same communications
link. A DCP link is made up of
two 64-kbps information (1)
channels and one signaling
(S) channel similar to the B
and D channels used in an
Integrated Services Digital
Network (lSDN).
digital switch element (DSE)
A device in each jack on
each module in the
communications system
control unit that interfaces
with the TDM (time-division
multiplex) bus.
digital transmission
A mode of transmission in
which the information to be
transmitted is first converted
to digital form and then
transmitted as a serial stream
of pulses. See also analog
transmission.
DIP (dual in-line package)
switch
A switch on a 400EM module
used to select the signaling
format for tie-line
transmission. DIP switches
are also used on other
equipment for setting
hardware options.
direct facility termination
(DFT)
A central office (CO)
line/trunk that terminates
directly on one or more
telephones; in PBX mode a
DFT cannot be part of a trunk
pool.
direct inward dialing (DID)
A service that transmits the
called station number to the
communications system from
the central office (CO) and
routes incoming calls directly
to the called station, calling
group, or outgoing trunk pool,
bypassing the system
operator.
Direct Station Selector (DSS)
A 60-button adjunct that
enhances the call-handling
capabilities of an MLX-20L™
telephone or MLX-28D™
telephone when used as an
operator console.
display buttons
The buttons on an MLX
display telephone used to
access the telephone's
display.
Glossary GL-9