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AMPS (Advanced Mobile Phone System) is
a somewhat ironic name for the original
cellular system authorized in the United
States. It uses an analog FM radio link and it
is very easy to eavesdrop on it. AMPS is
particularly inefficient in use of spectrum
compared to any of the digital standards.
Generally AMPS still has the best coverage of
any of the standards (solely due to its ten
year head start on buildout), but that's about
the only thing it has going for it. Sound
quality is generally worse than any of the
digital standards.
Bit within the context of CDMA is
distinct from chip and refers to a payload
binary digit. Each bit is represented by many
chips. Bits contain information and are subject
to the laws of Information Theory.
ASIC stands for Application-specific integrated
circuit
ACD stands for Automatic Call Distributor
ABR stands for Area Border Router
ADM stands for Add-Drop Multiplexer
APON stands for ATM Passive Optical Network
ARP stands for Address Resolution Protocol
AS stands for Autonomous System
ASBR stands for
Autonomous System Boundary Router
ASP stands for Active Server Pages
ASIC stands for Application Specific Integrated
Circuits
ATM stands for Asynchronous Transfer Mode
A
Angstrom
A measure of optical wavelength equal to one
hundred-millionth of a centimeter. This unit of
measure is being replaced by nanometers.
A&B
Bit Signaling Procedure
used in T1 transmission facilities in which
each of the 24 T1 subchannels devotes 1 bit of
every sixth frame to the carrying of
supervisory signaling information. Also called 24th
channel signaling.
A3
GSM
authentication algorithm
A5
GSM
stream cipher algorithm
A8
SM
cipher key generating algorithm (GSM)
AAA
stands
for
Authentication, Authorization, Accounting
Pronounced "triple a."
AALATM
Adaptation Layer
The AAL enables engineers to adapt the ATM
layer to particular services. It lies between
the ATM layer and the higher layers and maps or
adapts the functions or services of the higher
layers onto a common ATM bearer service.
AAR
Automatic
Alternative Routing
A system for providing continued
telecommunications service in the event that a
primary transmission route fails
catastrophically.
AARP
AppleTalk
Address Resolution Protocol
Protocol in the AppleTalk protocol stack that
maps a data-link address to a network address.
AAV
Alternate
Access Vendors
ABC
Advanced
Broadband Communications
ABCD
Signaling 4-bit
telephony signaling coding in which each letter
represents 1 of the 4 bits. This is often
associated with CAS or robbed-bit signaling on
a T1 or E1 telephony trunk.
A-bis
BSC-BTS
interface
ABMA
synchronous Balanced Mode
HDLC (and derivative protocol) communication
mode supporting peer-oriented, point-to-point
communications between two stations, where
either station can initiate transmission.
ABR
1.
Available Bit Rate
QoS class defined by the ATM Forum for ATM
networks. ABR is used for connections that do
not require timing relationships between source
and destination. ABR provides no guarantees in
terms of cell loss or delay, providing only
best-effort service. Traffic sources adjust
their transmission rate in response to
information they receive describing the status
of the network and its capability to
successfully deliver data.
2. Area Border Router Router located on the border of one or more OSPF areas that
connects those areas to the backbone network.
ABRs are considered members of both the OSPF
backbone and the attached areas. They therefore
maintain routing tables describing both the
backbone topology and the topology of the other
areas.
ABS
Alternative
Billing Services
These are IN services that allow subscribers to
charge a call to a number or telephone other
than the one they are using-for example, by
using a charge card, credit card or personal
identification number.
AC
Access
Charge
Monies collected by local telephone companies
for use of their circuits to originate and
terminate long-distance calls. Access charges
can be per minute fees levied on long-distance
companies; subscriber line charges (SLCs)
levied directly on regular local lines; fixed
monthly fees for special telephone company
circuits such as WAL, DAL, and T-1; or special
access surcharges levied on special access
circuits.
Acceptance
Mask A
collection of thresholds assigned to circuit
performance parameters. When used during
circuit testing, it automatically reports
whether a particular performance parameter has
failed.
Access1.
The method, time, circuit, or facility used to
enter the network.
2. The
service provided by local exchange carriers or
alternate access providers, that connects an
interexchange carrier with its customers.
Switched access provides such service over the
public switched network; special access
provides dedicated access for private line
services and sometimes at the closed end of
switched services.
3. To
retrieve information from a storage medium.
such as videodisc, CD-ROM, computer disc or
videotape.
Access
Bandwidth The
ability of a communications network to provide
bandwidth dynamically so users will receive
service regardless of the bandwidth their
service request requires.
Access
Code A
digit or digits presented to telecommunications
equipment that permits the user to connect to a
given service. In private branch exchange (PBX)
operation, access code is the digits that are
dialed connecting a telephone user to a
specific trunk group or to a special service
such as paging or dictation. The term is also
frequently applied to the "1" dialed
in many local telephone company areas for the
completion of an interexchange toll call.
Access
List List
kept by routers to control access to or from
the router for a number of services (for
example, to prevent packets with a certain IP
address from leaving a particular interface on
the router).
Access
Method In
local area networks, the technique and/or
program code used to arbitrate the use of the
communications medium by granting access
selectively to individual stations. Examples
are carrier sense multiple access/collision
detection (CSMA/CD) and Token Passing.
Access
Router An
access device with built-in basic routing
protocol support, specifically designed to
allow remote LAN access to corporate backbone
networks. Not designed to replace backbone
routers or to build backbone networks.
Access
Time1.
The time interval between the instant at which
an instruction control unit starts a call for
data and the instant at which delivery of data
is completed.
2. The time
interval between the instant data is requested
to be stored and the instant storage is begun.
3. The total
time required to find, retrieve, and display
data after initiation of a retrieval command.
Access time is usually measured at its worst,
or the longest possible time it takes to get
from one section of the medium to another. This
is generally a matter of minutes on videotape
two or fewer seconds on videodisc or CD, and
milliseconds or microseconds on a computer.
ACCH
stands
for
Associated Control Channel
AC-DC
Ringing A
system in which telephone ringing uses
alternating current to operate a ringer and
direct current to stop the ringing when the
called party answers.
ACDS
Automatic
Call Distribution Systems Used by telephone companies and private
businesses for managing high volumes of
incoming calls.
ACE
Advanced
Communications Experiments
ACF
Advanced
Communications Function
IBM software products that incorporate IBM's
system network architecture (SNA) and
administer intercommunications between
computers.
ACITS
Advisory
Committee on Information Technology
Standardization
ACK
Acknowledgment
Code
A method in which one or more characters are
generated at a receiving device to indicate the
information has been received correctly.
ACR
Allowed
Cell Rate
Parameter defined by the ATM Forum for ATM
traffic management. ACR varies between the MCR
and the PCR, and is dynamically controlled
using congestion control mechanisms.
ACS
Asynchronous
Communications Server
A LAN server that enables a network user to
dial out of the network and into the public
switched telephone network (PSTN), or to access
nailed-up lines for asynchronous
communications. An asynchronous communications
server is also called a dial-in/dial-out server
or a modem server.
ACSE
Association
Control Service Element
OSI convention used to establish, maintain, or
terminate a connection between two
applications.
Active
Hub Multiported
device that amplifies LAN transmission signals.
AD
Administrative
Domain
Group of hosts, routers, and networks operated
and managed by a single organization.
Adaptive
Equalization A
technique that allows a modem to continuously
analyze and compensate for variations in the
quality of a telephone line.
Adaptive
Routing A
form of routing in which messages are forwarded
through the network along the most
cost-effective path available. Messages are
automatically rerouted as required by changes
in the network topology if, for example, a
circuit becomes disabled.
ADC
Access
Deficit Charge
ADCCP
Advanced
Data Communications Control Protocol
ANSI standard bit-oriented data link control
protocol.
Address1.
A set of numbers that uniquely identifies
something: a workstation on a LAN, a location
in computer memory, or a packet of data
traveling through a network.
2. A
designator defining the unique ID of a
terminal, peripheral device, or other nodal
component in a network.
Address
Mask A
32-bit-long mask used to select an Internet
protocol (IP) address for subnet addressing.
The mask selects the network portion of the IP
address and one or more bits of the local area
network (LAN) address.
Address
Translation1.
The process of converting external addresses
into standardized network addresses and vice
versa.
2. Facilities
interconnection of multiple networks that each
have their own address plan.
ADM
Add
Drop Multiplexer
In OSS, a multiplexer that allows a signal to
be added into or dropped out of a SONET span.
ADMD
Administrative
Management Domain X.400 Message Handling System public carrier. The
ADMDs in all countries worldwide together
provide the X.400 backbone.
ADONIS
The
submarine cable between France and Greece.
ADPCM
Adaptive
Differential Pulse Code Modulation
process by which analog voice samples are
encoded into high-quality digital signals.
ADS
Asynchrous
Data Switching
A private branch exchange (PBX) system that
supports asynchronous data.
ADSL
(Asymmetric
Digital Subscriber Line) is
a digital local loop typically using copper
facilities and providing greater bandwidth in
one direction than the other. ADSL is expected
to provide a voice channel for calls over the
public switched network, a bi-directional
low-speed data channel, and a unidirectional
1.5 Mbps channel between the central office
(CO) and the customer premise.
ADU
Automatic
Dialing Unit
A device that is programmed with frequently
called numbers. The caller presses one to three
digits and the preprogrammed number is
automatically dialed into the telephone
circuit.
AEGUS
The
submarine cable between Greece and Crete.
AFIPS
American
Federation of Information Processing Societies
An organization of computer-related societies.
Members include the Association for Computer
Machinery, the Institute of Electrical and
Electronic Engineers Computer Group, Simulation
Councils, Inc., and American Society for
Information Science.
AGC
Automatic
Gain Control
A process that levels out high and low levels
of sound to improve the consistency of the
recording.
Agent1.
Software that processes queries and returns
replies on behalf of an application.
2. In NMSs,
process that resides in all managed devices and
reports the values of specified variables to
management stations.
Aggregate
Bandwidth The
total bandwidth of channel carrying a
multiplexed bit stream.
Aggregator
1.
An independent entity that brings several
subscribers together to form a group that can
obtain long-distance service at a reduced rate.
Subscribers are billed by the original
interchange carrier (IXC). The aggregator only
provides the initial set-up of the plan, and
usually provides no service after that. An
aggregator is not a reseller.
2. Any person
or business that makes telephones available to
the public or to transient users of its
premises. This includes hotels, motels,
universities operating dormitories, hospitals,
and pay telephone operators.
AI
Artificial
Intelligence
The capacity of a device to perform human
intelligence functions, such as reasoning,
learning, and self-improvement.
AIM
Ascend
Inverse Multiplexing Protocol
An in-band protocol used to manage the
interconnection of two remotely located inverse
multiplexers.
AIN
Advanced
Intelligent Network
A switched voice and data network consisting of
a variety of network elements. It refers to
open interfaced, multi-vendor,
telecommunications capabilities that let phone
companies create and customize their service
offerings. Also, often used as shorthand for
the next-generation INs.
AIOA
synchronous Input/Output
AIOD
(Automatic
Identification of Outward Dialing) is
a
hardware system or private branch exchange
(PBX) feature that automatically obtains the
identity of a calling station over a separate
data link for automatic message accounting.
AIS
Alarm
Indication Signal
In a T1 transmission, an all-ones signal
transmitted in lieu of the normal signal to
maintain transmission continuity and to
indicate to the receiving terminal that there
is a transmission fault that is located either
at, or upstream from, the transmitting
terminal.
Alarm
SNMP
message notifying an operator or administrator
of a network problem.
ALBO
Automatic
Line Build Out A method to ease data service unit (DSU) and channel service
unit (CSU) installation by enabling the DSU/CSU
to adjust signal output automatically according
to line distance.
Algorithm1.
A set of instructions or mathematical formulas
used to solve a given communications problem.
2. In audio,
video and data coding, the step-by-step
procedure (often including repetition) which
provides suitable compression and/or encryption
for the specific application. When used for
compression, this mathematical process results
in a significant reduction in the number of
bits required for transmission and may be
either lossless or lossy.
Alias1.
A name that users can use on a bulletin board
that is not their own. Also called handle.
2. A false
signal produced by the analog-to-digital
sampling process. Often caused by failure to
observe the Nyquist criterion and can create
artifacts which are subjectively disturbing.
Aliasing
A
form of image distortion associated with signal
sampling. A common form of aliasing is a
stair-stepped appearance along diagonal and
curved lines.
ALPALThe
submarine cable that links Algeria, Palma, and
Spain.
Alternate
Access A
form of local access where the provider is not
the local exchange carrier (LEC) but is
authorized or permitted to provide local access
service.
Alternate
Access CarriersLocal
exchange carriers that compete directly with
the regional Bell operating companies (RBOCs).
They are normally found only in the larger
metropolitan areas. Examples are Teleport and
Metropolitan Fiber Systems.
AM
Amplitude
Modulation
1. The technique of varying the amplitude or
wavelength of a carrier wave in direct
proportion to the strength of the input signal
while maintaining a constant frequency and
phase.
2. The
variation of carrier signal's strength
(amplitude) as a function of an information
signal.
AMA
Automatic
Messaging Accounting
In OSS, the automatic collection, recording,
and processing of information relating to calls
for billing purposes.
AMADNSAM
A Data Networking System In OSS, the next generation (formerly Bellcore)
system for the collection and transport of AMA
data from central office switches to a billing
system.
AMI
Alternative
Mark Inversion
Line-code type used on T1 and E1 circuits. In
AMI, zeros are represented by 01 during each
bit cell, and ones are represented by 11 or 00
alternately, during each bit cell. AMI requires
that the sending devices maintain ones density.
Ones density is not maintained independently of
the data stream. Sometimes called "Binary
Coded Alternate Mark Inversion."
AMITE
The
submarine cable between France and Morocco.
Amplitude
Maximum
value of an analog or a digital waveform.
AMPS
North
American (Advanced Mobile Phone Service)
A North American standard for mobile
telephones.
Analog
A
device or method that uses non-discrete
variations in frequency, amplitude, location,
and so forth to symbolize or carry sounds,
signals, mathematical data, or other
information. Analog technology mimics
information so that a voice is represented as
an electrical signal with frequency and
amplitude proportional to the pitch and volume
of the voice. Traditional telephone and video
are both analog technologies.
Analog
Channel A
channel that imposes no specified limits on
transmitted data. There are no discrete
packages or pulses of information.
Analog
Loopback A
test that checks whether the modem or data
terminal equipment (DTE) is causing errors in
data transmission. During an analog loop back,
the system sends data between the local modem
and the local DTE. Errors in transmission
indicate a problem with the modem, DTE, or the
interface between them.
Analog
Transmission Signal
transmission over wires or through the air in
which information is conveyed through the
variation of some combination of signal
amplitude, frequency, and phase.
ANCAll
Number Calling
Telephone calling numbers containing all
numerical digits instead of a combination of
two letters and five numbers.
ANI
Automatic
Number Identification
SS7 (signaling system 7)feature in which a
series of digits, either analog or digital, are
included in the call, identifying the telephone
number of the calling device.
ANNIBAL
The
submarine cable between France and Tunisia.
Anonymous
FTP Allows
a user to retrieve documents, files, programs,
and other archived data from anywhere on the
Internet without having to establish a userid
and password. By using the special userid of
anonymous, the network user will bypass local
security checks and will have access to
publicly accessible files on the remote system.
ANSI
American
National Standards Institute
ANSI creates standards for networking and
communications. It is the U.S. representative
to the International Standards Organization
(ISO)
ANTINEA
The
submarine cable between Senegal and Morocco.
Anycast
In
ATM, an address that can be shared by multiple
end systems. An anycast address can be used to
route a request to a node that provides a
particular service.
ANZCAN
The
submarine cable that links Australia, New
Zealand, and Canada.
AOCAll
Ones Code
A signal stream containing 15,360 or less zeros
in one second. When a device loses
synchronization, it sends an all ones code to
keep the network up. It also sends this code to
tell the network there is a transmission
problem.
AOS
Alternative
Operator Services
Business not associated with the telephone
company that provides operator services, for
example, to private pay phone companies.
APA
Access
Provider Architecture
The specifications of a system and the method
in which its subcomponents interconnect,
interact, and cooperate. Architectures are
often described in multiple levels of
abstraction from low-level physical to
higher-level logical application and end-user
views.
API
Application
Programming Interface
A programming interface for accessing and
administering ISDN services
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