Data Communication and Networking Glossary

Data Communication	Description
AAL (ATM Adaptation Layer)	A Collection of standardrized protocols that adapt user traffic to the cell format. The AAL is subdivided into the convergence sublayer (CS) and the segmentation and reassembly (SAR) sublayer, there are several types of AALs-AAL1,ALL2, AAL3/4 and AAL5.
Address	A coded representation of the origin or destination of data
ADPCM (Adaptive Differential Pulse code Modulation)	An ITU standard technique for encoding analog voice signals into a digital format 32 kbps
Agent	The managed system in SNMP
AMI (Alternate aMark Inversion)	A Bipolar coding schema in which successive ones (marks) must alternate in polarity
Analog	A-continuous wave or signal (such as human voice)
Analog loopback	A testing technique that isolates faults in transmission equipment by performing a loopback on the dataat the analog side of the modem.
Analog Transmission	The transmission of a continuously variable signal, as opposed to a discrete (digital) one.
ANSI	American National Standards Institute.
AR (Access Rate)	The data rate of the user access channel in a frame relay network.
ARQ (Automatic Request for repeat or Retransmission)	A Communication feature where the receiver ask the transmitter to resend a block or frame because error were detected by the receiver.
ASCII (American Standard code for Information Interchange)	A Seven level code (128 possible characters) used for data transfer.
Asynchronous Transmission	A Transmission method that sends units of data one character at a time, characters are preceded by start bits and followed by stop bits.
ATM (Asynchronous Transfer mode)	A Standard (ITU) implementation of cell relay, which is a packet switching technique using packets of fixed length.
ATM Forum	A world wide organization that promotes and sets standards for ATM networks and equipments.
Attenuation	Signal power loss through equipment, lines or other transmission devices.
AWG	The American wire Gauge system, which specifies wire width
Balanced	A Transmission line in which voltages on the two conductors are equal in magnitude, but opposite in polarity, with respect to ground
Bandwidth	The range of frequencies passing through a given circuit, the greater the bandwidth, the more information can be sent through the circuit in a given period time.