MERLIN LEGEND Communications System Release 6.0
System Programming
555-660-111 Issue 1
February 1998
Glossary
PageGL-11
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, transfer calls, make
outside calls for users with outward calling restrictions, set
up conference calls, and monitor system operation.
DNIS (Dialed Number Identification Service) Service provided by
AT&T and MCI; it routes 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 basic telephone jack and used at an
unattended extension or front desk.
DOS (disk operating system)
drop-and-insert
equipment A 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 o f few er tha n
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.
DSL (Digital Subscriber Line) A Digital Subscriber Line provides
full-duplex service on a single twisted metallic pair (2-wire)
at a rate sufficient to support ISDN Basic Rate Access.
DSS (Direct Station Selector) 60-button
adjunct
that enhances
the call-handling capabilities of an MLX-20L or MLX-28D
telephone used as an operator console.
DTE (data terminal equipment) Equipment that makes the
endpoints in a connection over a data connection; for
example, a data terminal, personal computer, host
computer, or printer.
DTMF signaling (dual-tone multifrequency signaling) Touch-tone signaling
from telephones using the voice transmission path. DTMF
signaling provides 12 distinct signals, each representing a
dialed digit or character, and each composed of two
voiceband frequencies.