Lucent Technologies Release 6 ユーザーズマニュアル
DEFINITY Enterprise Communications Server Release 6
Installation and Test for Multi-Carrier Cabinets
Installation and Test for Multi-Carrier Cabinets
555-230-112
Issue 5
May 1998
Glossary and Abbreviations
Page GL-16
dBA
Decibels in reference to amperes.
dBrnC
Decibels above reference noise with C filter.
DC
Direct current
DCE
Data-communications equipment
D-channel backup
Type of backup used with Non-Facility Associated Signaling (NFAS). A primary D-channel
provides signaling for an NFAS D-channel group (two or more PRI facilities). A second D-channel,
on a separate PRI facility of the NFAS D-channel group, is designated as backup for the
D-channel. Failure of the primary D-channel causes automatic transfer of call-control signaling to
the backup D-channel. The backup becomes the primary D-channel. When the failed channel
returns to service, it becomes the backup D-channel.
provides signaling for an NFAS D-channel group (two or more PRI facilities). A second D-channel,
on a separate PRI facility of the NFAS D-channel group, is designated as backup for the
D-channel. Failure of the primary D-channel causes automatic transfer of call-control signaling to
the backup D-channel. The backup becomes the primary D-channel. When the failed channel
returns to service, it becomes the backup D-channel.
DCO
Digital central office
DCP
Digital Communications Protocol
DCS
Distributed Communications System
DDC
Direct Department Calling
DDD
Direct Distance Dialing
delay-dial trunk
A trunk that allows dialing directly into a communications system (digits are received as they are
dialed).
dialed).
denying a request
Sending a negative acknowledgement (NAK), done by sending an FIE with a
return error
component (and a cause value). It should not be confused with the denial event report that applies
to calls.
to calls.
designated voice terminal
The specific voice terminal to which calls, originally directed to a certain extension, are redirected.
Commonly used to mean the forwarded-to terminal when Call Forwarding All Calls is active.
Commonly used to mean the forwarded-to terminal when Call Forwarding All Calls is active.
dial-repeating trunks
A PBX tie trunk that is capable of handling PBX station-signaling information without attendant
assistance.
assistance.
dial-repeating tie trunk
A tie trunk that transmits called-party addressing information between two communications
systems.
systems.
DID
Direct Inward Dialing