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8 Appendix I Glossary of Terms ADSL
Asymmetric Digital Subscriber Line: Modems attached to twisted pair copper
wiring that transmit from 1.5 Mbps to 9 Mbps downstream (to the subscriber) and
from 16 kbps to 800 kbps upstream, depending on line distance.
AGC
Automatic Gain Control, is an electronic system found in many types of devices.
Its purpose is to control the gain of a system in order to maintain some measure of
performance over a changing range of real world conditions.
ARP
Address Resolution Protocol is a protocol used by the Internet Protocol (IP)
[RFC826], pecifically IPv4, to map IP network addresses to the hardware
addresses used by a data link protocol. The protocol operates below the network
layer as a part of the interface between the OSI network and OSI link layer. It is
used when IPv4 is used over Ethern et
ATA
Analogue Telephone Adapter. Covert analogue telephone to be used in data
network for VoIP, like Grandstream HT series products.
CODEC
Abbreviation for Coder-Decoder. It's an analog-to-digital (A/D) and digital-to-
analog (D/A) converter for translating the signals from the outside world to
digital, and back again.
CNG
Comfort Noise Generator, geneate artificial background noise used in rad io and
wireless communications to fill the silent time in a transmission resulting from
voice activity detection.
DATAGRAM
A data packet carrying its own address information so it can be independently
routed from its source to the destination computer
DECIMATE
To discard portions of a signal in order to reduce the amount of information to be
encoded or compressed. Lossy compression algorithms ordinarily decimate while
subsampling.
DECT
Digital Enhanced Cordless Telecommunications: A standard developed by the
European Telecommunication Standard Institute from 1988, governing pan-