Animated Optical Glossary
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EXFO Glossary

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AbsorptionACTAerial Cable
ACCAdd-Drop Multiplexer (ADM)AIS
Access Network Address Resolution Protocol (ARP)AIS-L
Access Nodes ADM
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Acronym for: Access-border gateway function


Acronym for: Available bit rate


The transformation of light into heat as it passes through a dense medium.


Acronym for: Abort sequence


Acronym for: Accept

Access Network

Portion of a public switched network that connects access nodes to individual subscribers. The access network is predominantly passive, twisted-pair copper wiring.

Access Nodes

Points on the edge of the access network that concentrate individual access lines into a smaller number of feeder lines. Access nodes may also perform various forms of protocol conversion. Typical access nodes are digital loop carrier systems concentrating individual voice lines to T1 lines, cellular antenna sites, private branch exchanges and optical network units (ONUs).


Acronym for: Acknowledgement


Acronym for: Acceptable call quality


Acronym for: Activity


A circuit board installed in a computing device to connect it to a network. The adapter or NIC performs the hardware functions required to provide a computing device with physical communication capabilities. Also known as a network interface card (NIC).

Add-Drop Multiplexer (ADM)

An important element of an optical fiber network. A multiplexer combines, or multiplexes, several lower-bandwidth streams of data into a single beam of light. An add-drop multiplexer also has the capability to add one or more lower-bandwidth signals to an existing high-bandwidth data stream, and at the same time can extract or drop other low-bandwidth signals, removing them from the stream and redirecting them to some other network path.

Address Resolution Protocol (ARP)

A network-layer protocol used in TCP/IP transmission. ARP is used by end stations to determine the physical address of other stations on the same LAN.


Acronym for: Additional digital service

Aerial Cable

An armored, buffered tube fiber cable, designed for suspension on telephone poles or electrical transmission towers. Used as an alternative to buried cable and widely deployed in local loops.


Acronym for: Access gateway


Acronym for: Alarm indication signal


Acronym for: Line alarm indication signal