MERLIN LEGEND Communications System Release 7.0
System Programming
555-670-111
Issue 1
April 1999
Glossary
GL-11
Digital Subscriber
Line
See
Digital
Transmission
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
.
DIP Switch
Dual In-line Package
. Switch on a 400EM module used to
select the signaling format for tie-line transmission. Also
used on other equipment for setting hardware options.
Direct Facility
Termination
DFT
. See
.
Direct Inward Dial
See
.
Direct-Line
Console
See
.
Direct Station
Selector
See
Display Buttons
Buttons on an MLX display telephone used to access the
telephone’s display.
DLC
Direct-Line Console
. Telephone used by a system operator
to answer outside calls (not directed to an individual or a
group) and inside calls, to transfer calls, to make outside
calls for users with outward calling restrictions, to set up
conference calls, and to monitor system operation.
DNIS
Dialed Number Identification Service
. Service provided by
AT&T and MCI to route incoming 800 or 900 calls
according to customer-selected parameters, such as area
code, state, or time of call.
Door Answering
Unit
Device connected to a
tip/ring
jack and used at an
unattended extension or front desk.
DOS
Disk Operating System
.
Drop-and-Insert
Equipment
Device that can be installed between systems connected
by
tandem PRI trunks
or T1-Emulated
tandem tie trunks
to
allow fractional use of the facility—that is, use of fewer than
23 of the PRI
B-channels
or fewer than 24 of the T1
channels
. In a PRI facility, the equipment must never drop
Channel 24, the
D-channel
. All channels must still be
programmed and all count towards the system maximum of
80 lines.
DS0
Digital Signal 0
. Single 64-kbps voice or data channel.
DS1
Digital Signal 1
.
Bit
-oriented signaling interface that
multiplexes twenty-four 64-kbps channels into a single
1.544-mbps stream.