User manual

Glossary-8 July 2004 Wide Bank 28 DS3 - Release 2.4
Glossary
Customer Premises
Equipment
CPE. Items of telecommunications equipment, such as key systems, PBXs, answering
machines, and CSU/DSUs, which reside on the customer’s premises past the network
interface.
Cyclic Redundancy
Check
CRC. A technique for using overhead bits to detect transmission errors.
Data Terminal
Equipment
DTE. In the EIA/TIA 232E standard specification, the RS-232 interface is connected
between the DCE (Data Circuit-Terminating Equipment) and the DTE. The main
difference between the DCE and the DTE is the pins two and three are reversed. The ABII
uses an RS-232 port for management and asynchronous and synchronous data
transmission.
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.
Digital Loop Carrier DLC. Digital Loop Carriers are specialized SONET back-to-back mux 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.
DS0 Digital Signal level 0. 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 Digital Signal level 1. A digital signal at 1.544 million bits per second (Mbps) in North
America and at 2.048 Mbps elsewhere.
DS3 Digital Signal level 3. A digital signal at 44.736 million bits per second (Mbps), the
equivalent of 28 DS1 signals.
DSX-1 Digital Signal Crossconnect level 1. Refers to equipment that crossconnects DS1 rate
signals, typically over short distances from zero to 660 feet.
DSX-3 Digital Signal Crossconnect level 3. Refers to equipment that crossconnects DS3 rate
signals, typically over short distances from zero to 660 feet.
E1 The European CEPT digital signal similar to the North American DS1 except that the E1
information rate is 2.048 Mbps and transports 30 DS0 signals, compared to the 24 DS0
signals in the North American DS1. E1 uses separate 64 Kbps channels for synchronization
and signaling, so all 8 bits of the DS0 are used to code the wave shape of the digitized voice
sample.