Carrier Access user manual Access Navigator Release August GlossaryGlossary-7

Glossary

Data Terminal Equipment

Digital Data Link

Defect

Demultiplexing

Digital

Crossconnect

System

Digital Loop Carrier

Digital Signal

Direct Inward Dial

Digital Signal level 0

Digital Signal level 1

Digital Signal Crossconnect level 1

DSX-1 Equalization

DTE. See description at Data Communications Equipment (DCE).

DDL. An out-of-band communications link used in SLC-96/TR-08 digital loop carrier systems for traffic maintenance and call setup.

A limited interruption in the ability of an item to perform a required function.

A process applied to a multiplex signal for recovering signals combined within it and for restoring the distinct individual channels of the signals.

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.

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).

An electrical or optical signal that varies in discrete steps. Electrical signals are coded as voltages, optical signals are coded as pulses of light.

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.

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.

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.

DSX-1. Refers to equipment that crossconnects DS1 rate signals, typically over short distances up to 660 feet.

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.

Access Navigator - Release 1.8 August 2003 GlossaryGlossary-7