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Access Navigator - Release 1.8 August 2003 GlossaryGlossary-7
Glossary
Data Terminal
Equipment
DTE. See description at Data Communications Equipment (DCE).
Digital Data
Link
DDL. An out-of-band communications link used in SLC-96/TR-08 digital loop
carrier systems for traffic maintenance and call setup.
Defect A limited interruption in the ability of an item to perform a required function.
Demultiplexing A process applied to a multiplex signal for recovering signals combined within it
and for restoring the distinct individual channels of the signals.
Digital
Crossconnect
System
DCS. An electronic crossconnection that has access to lower-rate channels in
higher-rate multiplexed signals and can electronically rearrange (crossconnect)
those channels. The Access Navigator provides DCS 1:0 level switching, which
means that it can crossconnect both DS1 and DS0 signals. The DCS switching
configuration must typically be set up in advance and remain in place until
changed by an operator.
Digital Loop
Carrier
DLC. Digital Loop Carriers are specialized SONET back-to-back multiplexing
systems providing circuit concentration in the local loop market. The elements
used are similar to the Terminal Mux but transmission speed is normally limited
to 155 Mbit/s (OC-3).
Digital Signal An electrical or optical signal that varies in discrete steps. Electrical signals are
coded as voltages, optical signals are coded as pulses of light.
Direct Inward
Dial
DID. The ability for a caller outside a company to call an internal extension
without assistance or additional steps. The dialed digits are passed from the central
office to the subscriber’s PBX, which then connects the call to the proper
extension.
Digital Signal
level 0
DS0. The basic digital signal at 64,000 bits per second (bps) used to transport
8,000 data bytes or voice samples per second over telecommunications networks.
Digital Signal
level 1
DS1. A digital signal at 1.544 million bits per second (Mbps) in North America
where it is used with T1 facilities, and at 2.048 Mbps elsewhere where it is called
E1. The equivalent of 24 DS0 signals in North America and 30 DS0 signals
elsewhere.
Digital Signal
Crossconnect
level 1
DSX-1. Refers to equipment that crossconnects DS1 rate signals, typically over
short distances up to 660 feet.
DSX-1
Equalization
Shaping of the transmit signal wave form to meet the requirements of Digital
Signal Crossconnect, level 1 transmissions between central office equipment. The
amount of equalization depends on the length of interconnecting cable and is
usually selectable in fixed ranges, measured in feet.