DEFINITY ECS Release 8.2
Administrator’s Guide
555-233-506 Issue 1
April 2000
Glossary and abbreviations
1628
dial-repeating trunks
A PBX tie trunk that is capable of handling PBX station-signaling information without attendant assistance.
dial-repeating tie trunk
A tie trunk that transmits called-party addressing information between two communications systems.
DIDDirect Inward Dialing
digit conversion
A process used to convert specific dialed numbers into other dialed numbers.
digital
The representation of information by discrete steps. See also analog.
digital communications protocol (DCP)
A proprietary protocol used to transmit both digitized voice and digitized data over the same commun ications
link. A DCP link is made up of two 64-kbps information (I-) channels and one 8-kbps signaling (S-) channel.
The DCP protocol supports two information-bearing channels, and thus two telephones/data mo du les. Th e I 1
channel is the DCP channel assigned on the first page of the 8411 station form. The I2 channel is the DCP
channel assigned on the analog adjunct page of the 8411 station form or on the data module page.
Digital Communications Protocol. The DCP protocol supports two information- be aring channels, and thus
two telephones/data modules. The I1 channel is the DCP channel assigned on the first page of the 8411 statio n
form. The I2 channel is the DCP channel assigned on the analog adjunct page of the 8411 station form or on
the data module page.
digital data endpoints
In DEFINITY ECS, devices such as the 510D terminal or the 515-type business communicati ons terminal
(BCT).
digital multiplexed interface (DMI)
An interface that provides connectivity between a communications system and a host computer or between
two communications systems using DS1 24th-channel signaling. DMI provides 23 64- kbps data channels and
1 common-signaling channel over a twisted-pair connection. DMI is offered th r ough two capabilities: bit-ori-
ented signaling (DMI-BOS) and message-oriented signaling (DMI-MOS).
digital signal level 0 (DS0)
A single 64-kbps voice channel. A DS0 is a single 64-kbps channel in a T1 or E1 facility and consists of eight
bits in a T1 or E1 frame every 125 microseconds.
digital signal level 1 (DS1)
A single 1.544-Mbps (United States) or 2.048-Mbps (outside the U nit ed Sta te s ) dig ita l s ig na l c a rr ie d on a T1
transmission facility. A DS1 converter complex consists of a pair, one at each end, of DS1 converter circuit
packs and the associated T1/E1 facilities.
digital terminal data module (DTDM)
An integrated or adjunct data module that shares with a digital telephone the same physical port for connec-
tion to a communications system. The function of a DTDM is similar to that of a PDM and MPDM in that it
converts RS-232C signals to DCP signals.
digital-to-analog converter (DAC)
A device that converts data in digital form to the corresponding analog signals. See also analog-to- digital con-
verter (ADC).
digital transmission
A mode of transmission in which information to be transmitted is first converted to digital form and then
transmitted as a serial stream of pulses.