258 Glossary
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D-channel (Data channel)
An ISDN standard transmission channel which is packet-switched. The channel is used for
call setup, signaling, and data transmission.
data link connection indentifier (DLCI)
The DLCI is used to identify a PVC in frame relay networks.
Delayed Ring Transfer (DRT) to prime
This feature allows the system to transfer unanswered calls on external line to the prime
telephone related to the called set. The number of rings can be adjusted. Activate this
feature under Feature settings in System programming.
dial-up connection
A dial-up connection is a temporary connection between computers. This connection is
established over an analog or digital telephone line.
dialing restriction
Restrictions are numbers you cannot dial when the dialing filter with those numbers is in
effect.
Digital Private Network Signaling System (DPNSS)
DPNSS is a networking protocol that provides operators with access to Business
Communications Manager features over multiple combined networks. Corporate offices,
separated geographically, can be linked over DPNSS to other Business Communications
Manager systems, bypassing the restrictions of the PSTNs to which they may be
connected. This allows connected Business Communications Manager systems to function
like a private network. DPNSS is available for International systems only.
directory number (DN)
A unique number that the Business Communications Manager system assigns to every
telephone or data terminal.
disconnect supervision
A feature that enables the system to detect if an external caller hangs up. Enable
Disconnect Supervision under Trunk/Line data in Lines programming.
disk mirroring
The Business Communications Manager supports the RAID 1 disk mirroring protocol,
which creates an exact data duplicate of the system hard disk on a second, co-located hard
disk within the BCM1000. If one of the hard disks becomes inoperable, the system halts
the mirroring process and boots from the unaffected hard disk. You can then schedule disk
replacement during normal maintenance periods. This does not replace your BRU backup
disks, which should still be run on a regular schedule and be kept off-site.