Instruction manual

GLOSSARY
Covering User
The person at an alternate answering position who answers a redirected call (the coverage
receiver).
D4 Framing
D4 is the most prevalent framing format found in the T1 environment and is supported by
the D4 series channel banks.
DACS: (Digital Access and Cross-Connect)
DCE: (Data Communications Equipment) DDC: (Data Dial Code)
DDD: (Direct Distance Dialing)
DID: (Direct Inward Dialing)
DGC: (Direct Group Calling)
DMI-BOS (Digital Multiplexed Interface-Bit Oriented Signaling)
See Common Channel Signaling.
DSn
Generally, Digital Signal (DS) level n refers to the logical organization or division of the
bandwidth available on T carriers. DS0 is a single 64 kbps channel. Twenty-four DS0
channels combine to form a DS1 channel. Four DS1 channels combine to form a DS2
channel. Twenty-eight DS1 channels combine to form a DS3 channel.
DTAC: (Direct Trunk Attendant Console)
DTE: (Data Terminal Equipment)
DTU: (Digital Tape Unit)
DTMF: (Dual Tone Multifrequency)
DXS: (Direct Extension Selector)
Data Channel
A communications path between two points used to transmit digital signals.
Data Communications Equipment (DCE)
Refers to a specific RS-232C interface connector configuration. DCE devices are designed
to interface directly (pin-for-pin) to Data Terminal Equipment (DTE). The transmit and
receive pins are reversed from that of a DTE interface. A modem is an example of a DCE
device.
November 1995
9-5