Cable, Networking Acronyms, Glossary and Terms
A
Absorption: One cause of attenuation where light signal is absorbed
into the glass during transmission.
Access Method: A software/hardware method of transferring data between
host-resident application programs and remote device.
ACK or Acknowledge: A character or sequence of characters sent by a
receiver to notify a sender that the last message was received correctly, ACK
is also sent by a remote device as a "go ahead" response to a selection
sequence.
Acoustic Coupler: A type of modem that permits use of a telephone handset
as a connection to the public telephone network for data transmission by means
of sound transducers.
Adaptive differential pulse code modulation: One of the methods of pulse
code modulation utilised in digitising an analogue signal.
Adaptive equalisation: A modem feature allowing it to automatically
compensate for distortion on the line.
Algorithm: A prescribed set of well defined rules or processes for arriving
at a solution to a problem. A mathematical process.
Alphanumeric: made up of letters (alphabetic) and numbers (numeric)
Alternative route: A secondary communication path used to reach a destination
if the primary path is unavailable.
Alternative route: A secondary communication path used to reach a destination
if the primary path is unavailable.
Ambient noise: Signal interference that is present on a communication
line at all times (background noise)
American Wire Gauge, AWG: A US standard set of non-ferrous
wire conductor sizes. Typical data wiring is AWG number 24, 26 or 28. The higher
the gauge number, the smaller the diameter and the thinner the wire.
Amplitude modulation: Transmission of information on a communication
line by varying voltage level or amplitude.
Amplifier: A device that increases the power or amplitude of a signal.
Amplitude variation (ripple): unwanted variation of signal voltage at
different frequencies on a communication line.
Analogue signal: A signal that changes in a non-discrete manner (smooth
transmission to a different levels).
Answer back: A transmission from a receiving data processing device
in response to a request from a transmitting data processing device that it is
ready to accept or has received data.
ARQ, Automatic re-transission request: A generic description
of a protocol mechanism that involves retransmission of message blocks received
in error. There are several type of ARQ operation.
Asynchronous: A data transmission which does not require a separate
clock signal for the reception of data. In code sets, character codes containing
start and stop bits.
Asynchronous Transfer Mode, ATM: A very high speed network utilising
SONET optical transmission methods through the public telecommunications system.
Asynchronous transmission (start - stop transmission): Provides transmission
of one character at a time with a start bit and one or more stop bits appended
on each one. Any amount of time can elapse before the next character can be sent.
Attenuation, Insertion Loss: Loss of power.
Attenuation is usually measured in dB loss per length of cable (ex. 31.0 dB/100Ft.).
Attenuation increases as frequency increases.
Audio frequencies: Frequencies that can be heard by the average human
ear, usually 15 to 20,000 Hz.
Automatic dialler: A device that will automatically dial telephone numbers
on the network. Operation of the dialler may be manual or automatic
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