ADSL
ATM
Architecture
Asymetric digital subscriber
line(ADSL)
Access Line
Access Rate
Adapter Card
Application Service Provider (ASP)
Asynchronous Transfer Mode (ATM)
Asynchronous Transmission
Backbone
Bandwidth
Baseband
BGP
Broadband
Call Centre
Carrier
Channel
Circuit Switching
Circuit-Switched Network
Client/Server Architectures
Colocation
Compression
Computer telephony integration: CTI.
Customer Premises Equipment (CPE)
Data Terminal Equipment (DTE)
Direct dial inward (DDI)
Dedicated Line
Demodulation
Dial up
Digital Subscriber Line
Downstream
e-Commerce
Enterprise Network
Ethernet
Exchange lines
Fast Ethernet
Fibre Optic Cable
Firewall
Fixed Wireless
Frame Relay
Gpbs
GSM
Hub
Hypertext mark up language: HTML.
Interface
Internet
Internet Access
Internet Protocol
Internet Service Provider (ISP)
ISDN
ISP
Kilobits per second (Kbps)
Kilostream
Leased Line
LAN (Local Area Network)
Local Loop
MPEG
MPEG1
MPEG2
Megabits per second (Mbps)
Megastream
Modem
Modulation
Multiplexor
Network
Network Management System (NMS)
Packet
Packet Switched Network
Packet Switching
Peering
Proprietary
Protocol
Public Switched Telephone Network
PSTN
Redundancy
Router
Satellites
Server
Set top Box
Signalling
Synchronous Transmission
T-1 Carrier
Telco
Telecommuting
Terminal Adapter
UPS
Videoconferencing
Video on Demand
Voice Mail
Voice over IP
VPN
WAN
WLL
World wide web
X.25
ADSL
Asymmetric digital subscriber line, a new technology that allows more data to be
sent over existing copper telephone lines (POTS). ADSL supports data rates of
from 1.5 to 9 Mbps when receiving data (known as the downstream rate) and from
16 to 640 Kbps when sending data (known as the upstream rate).
ATM
Asynchronous Transfer Mode, a network technology based on transferring data in
cells or packets of a fixed size. The cell used with ATM is relatively small
compared to units used with older technologies. The small, constant cell size
allows ATM equipment to transmit video, audio, and computer data over the same
network, and assure that no single type of data hogs the line.
Architecture
The overall design of hardware or software. If the description is open
architecture, this means it is generally compatible with major applications.
Asymetric digital subscriber line (ADSL)
A method of transmitting at speeds up to 7 Mbps in one direction over a single
copper line, with up to 640 kbps in the opposite direction
Access Line
The physical telecommunications circuit connecting an end user location with the
serving central office in a local network environment. Also called the local
loop or "last mile."
Access Rate
The transmission speed of the physical access circuit between the end user
location and the local network. This is generally measured in bits per second.
Also called Access Speed.
Adapter Card
Circuit board or other hardware that provides the physical interface to a
communications network; an electronics board installed in a computer which
provides network communication capabilities to and from that computer; a card
that connects the DTE to the network. Also called a network interface card (NIC).
See also Data Termination Equipment, Network Interface Card.
Application Service Provider (ASP)
A company that offers a contractual service for deploying hosting and managing
packaged software from a central facility.
Asynchronous Transfer Mode (ATM)
A protocol that packs digital information into 53-byte cells (5 byte header and
48 bytes of payload) that are switched throughout a network over virtual
circuits. Standardized by the ITU-T in 1988 to create a Broadband Integrated
Services Digital Network (B-ISDN). Its ability to accommodate multiple types of
media (voice, video, data) makes it a likely player for full service networks
based on ADSL and VDSL.
Asynchronous Transmission
Data transmission one character at a time to the receiving device, with
intervals of varying lengths between transmittals, and with start bits at the
beginning and stop bits at the end of each character, to control the
transmission. In xDSL and in most dial up modem communications, asynchronous
communications are often found in Internet access and remote office
applications.
Backbone
That part of a network, which is used as the main path for carrying traffic
between network endpoints.
Bandwidth
Bandwidth is a measure of the amount of data that can be transmitted down
a telecommunication link. The rate of data flow is expressed in terms of the
number of data bits transmitted per second e.g. kbps(thousands of bits per
second) or Mbps(millions of bits per second).The broader the bandwidth the
larger the amount of data that can be sent. For example; a coaxial cable may
have a data rate of 140 Mbps, enough to carry, at any one time, the information
for two TV channels or nearly 300 music channels or about 2000 telephone
channels. Optical fibres have even greater data rates of 500 Mbps or more.
Coaxial cable is considered as broadband, whereas telephone wire (twisted pair)
is narrowband.
Baseband
Using the entire bandwidth of a transmission medium, such as copper cable, to
carry a single digital data signal.
BGP
Border Gateway Protocol, an Internet protocol that enables groups of routers to
share routing information so efficient, loop-free routes can be established. BGP
is commonly used within and between Internet Service Providers
Broadband
Sharing the bandwidth of a medium such as copper or fiber optic cable, to carry
more than one signal.
Call Centre
Where calls are handled by individuals who are trained to resolve those calls as
a one-stop shop, either for customer service, sales or enquiries. Call centres
are found in virtually all vertical industries, but are very common in banks,
insurance, airline and hotel sectors.
Carrier
A company supplying communications and related services to domestic and/or
business users.
Channel
A generic term for a communications path on a given medium; multiplexing
techniques allow providers to put multiple channels over a single medium. See
also Multiplexer.
Circuit Switching
A switching system that establishes a dedicated physical communications
connection between end points, through the network, for the duration of the
communications session; this is most often contrasted with packet switching in
data communications transmissions.
Circuit-Switched Network
Network that establishes a physical circuit temporarily on demand
(typically when a telephone or other connected device goes "off hook", and keeps
that circuit reserved for the user until it receives a disconnect signal.
Client/Server Architectures
A distributed computing model that involves distributing information
resources in servers which are accessed by so-called "clients", the end users.
This is generally opposed to centralized mainframe computing architectures.
Colocation
A server, usually a Web server, that is located at a dedicated facility designed
with resources which include a secured cage or cabinet, regulated power,
dedicated internet connection, security and support. These colocation facilities
offer the customer a secure place to physically house their hardware and
equipment as opposed to locating it in their offices or warehouse where the
potential for fire, theft or vandalism is much greater. Colocation facilities
offer high-security, including cameras, fire detection and extinguishing
devices, multiple connection feeds, filtered power, backup power generators and
other items to ensure high-availability which is mandatory for all Web-based,
virtual businesses.
Compression
The act of sampling and reducing a signal for the purposes of saving storage or
transmission capacity.
Computer telephony integration: CTI.
Where the computer and telephone interact with each other, enabling you to give
commands to the telephone through your PC, and vice versa.
Customer Premises Equipment (CPE)
A wide range of customer-premises terminating equipment which is connected to
the local telecommunications network. This includes telephones, modems,
terminals, routers, settop boxes, etc.
Data Terminal Equipment (DTE)
Typically the device that transmits data such as a personal computer or data
terminal.
Direct dial inward (DDI)
Enables you to dial directly into a company and reach an extension without
routing through a switchboard operator.
Dedicated Line
A transmission circuit that is reserved by the provider for the full-time use of
the subscriber. Also called a Private Line.
Demodulation
Conversion of a carrier signal or waveform (analog) into an electrical signal
(digital).
Dial up
The process of initiating a switched connection through the network; when used
as an adjective, this is a type of communication that is established by a
switched-circuit connection.
Digital Subscriber Line
A general term for any local network loop that's digital in nature; technically,
DSL equates to ISDN, but this is decreasingly enforced terminology.
Downstream
In xDSL, the communications from the network towards the customer premises.
e-Commerce
Trading where the transaction, including payment, takes place over the
Internet.
Enterprise Network
A term for a widely dispersed, multifaceted telecommunications network
for a particular purpose or organisation; a term for all of an organization's
telecommunications networking services and equipment.
Ethernet
A popular LAN standard. It handles low-level protocols and normally employs a
single coaxial cable. It is also possible to use thinner twisted pair cabling or
indeed fibre optics. Specially designed communications software is used to
control data transmission.
Exchange lines
Another name for telephone lines or trunks.
Fast Ethernet
A LAN used to connect devices within a single building or campus at speeds up to
100 Mbps. Within the OSI model, Fast Ethernet is defined at layer one (physical)
and layer two (data link). Also referred to as 100Base-T.
Fibre Optic Cable
A transmission medium composed of glass or plastic fibres; pulses of light are
emitted from a laser-type source. Fibre optic cabling is the present cabling of
choice for all inter exchange networks, and increasingly for the local exchange
loops as well; it is high security, high bandwidth, and takes of little conduit
space. Considered the physical medium of all future land-based communications.
Firewall
A firewall is a security measure that consists of a separate computer that acts
as a 'bouncer' between the Internet and an internal network. Its job is to sift
through all incoming traffic and turn away any undesirables and also to
implement security measures.
Fixed Wireless
Wireless devices or systems that are situated in fixed locations, such as an
office or home, as opposed to devices that are mobile, such as cell phones and
PDAs. Fixed wireless devices normally derive their electrical power from utility
mains, as opposed to portable wireless devices that normally derive their power
from batteries.
Frame Relay
A packet-switching protocol for connecting devices on a Wide Area Network (WAN).
Gpbs
Gigabits - 1,000,000,000 bits per second
GSM
Global System for Mobile Communications, one of the leading digital cellular
systems. GSM uses narrowband TDMA, which allows eight simultaneous calls on the
same radio frequency.
Hub
A common connection point for devices in a network. Hubs are commonly used to
connect segments of a LAN. A hub contains multiple ports. When a packet arrives
at one port, it is copied to the other ports so that all segments of the LAN can
see all packets
Hypertext mark up language: HTML.
The language protocol of the Internet, enabling all computers - whether PC or
Mac - anywhere in the world to share information. All documents need to be
translated into HTML in order to be viewed on the Internet. There are now many
packages that can do this automatically from a word processed document. See also
Internet protocol.
Interface
A point of connection between two systems, networks or devices.
Internet
A global network of computers, enabling anyone, anywhere in the world to contact
anyone else on the system, or view their documents. Sending messages is called
e-mail, viewing documents is called web browsing.
Internet Access
The physical telephone circuit connection between the subscriber and the nearest
Internet access node.
Internet Protocol
The language of the Internet, called HTML, Hyper text mark up language.
Internet Service Provider (ISP)
The telecommunications company providing subscriber access into the Internet.
ISDN
Integrated Services Digital Network, ISDN, is a telecommunications service which
has evolved from the existing public telephone network. ISDN is a network that
can transmit data, voice, image, and facsimile either separately or
simultaneously on the same network that carries regular telephone calls.
ISP
A company providing access to the internet.
Kilobits per second (Kbps)
A measure of bandwidth capacity or transmission speed. It stands for a thousand
bits per second.
Kilostream
The commercially available leased line service that operates at 64 Kbps.
Leased Line
A permanent telephone connection between two points set up by a
telecommunications common carrier. Typically, leased lines are used by
businesses to connect geographically distant offices. Unlike normal dial-up
connections, a leased line is always active.
LAN (Local Area Network)
A computer network that spans a relatively small area. Most LANs are confined to
a single building or group of buildings. These normally connect workstations and
personal computers
Local Loop
A generic term for the connection between the customer's premises (home, office,
whatever) and the provider's serving central office. Historically, this has been
a wireline connection; however, wireless options are increasingly available for
local loop capacity. Also colloquially referred to as "the last mile" (even
though the actual distance can vary).
MPEG
See Motion Picture Experts Group. ISO organization responsible for the
development for standards surrounding coded video and audio.
MPEG1
Compression scheme for full motion video. Compression algorithm introduced by
MPEG in 1991, the common goal of MPEG is compress 7.7 Meg down to about 150
Kbytes. MPEG 1 is designed to provide a resolution of 352 by 240 pixels at 30
frames per second.
MPEG2
Video compression standard selected by MPEG. Designed to provide a resolution of
720 by 480 pixels at 30 frames per second. Likely to be the leading compression
algorithm for a range of video applications including video of demand.
Megabits per second (Mbps)
A measure of bandwidth capacity or transmission speed. It stands for a million
bits per second.
Megastream
The commercially available leased circuit operating at 2.048 Mbps
Modem
A device that links a computer to other computers through a telephone line. The
modem enables a computer to send and receive binary data over a telephone line
by changing the bits into sound waves.
Modulation
The process whereby an electrical carrier wave is altered to facilitate the
transmission of a signal.
Multiplexor
A device which enables several different signals to be sent down the same
line.
Network
A group of two or more computer systems linked together to form LAn's and WAN's
Network Management System (NMS)
That system which allows a provider or end user to manage portions or all of a
telecommunications network; in xDSL, network management systems allow providers
to control and monitor those services based on the ADSL streams, at both the
physical and logical layers of the services.
Packet
A sub-unit of a data stream; a grouping of information that includes a header
(containing information like address destination) and, in most cases, user data.
Packet Switched Network
Network that does not establish a dedicated path through the network for
the duration of a session, opting instead to transmit data in units called
packets in a connectionless manner; data streams are broken into packets at the
front end of a transmission, sent over the best available network connection,
and then reassembled in their original order at the destination endpoint.
Packet Switching
A switching system that uses a physical communications connection only long
enough to transit a data message; data messages are disassembled into packets
and reassembled at the receiving end of the communication link; packets may
travel over many diverse communications links to get to the common endpoint.
This is most often contrasted with circuit switching in data communications,
where all data messages transmitted during a session are transmitted over the
same path for the duration of the session.
Peering
A relationship whereby two autonomous networks exchange traffic, generally using
BGP protocol.
Proprietary
A system or software design which means the system or software may only be
compatible with other products from the same vendor.
Protocol
An agreed-upon format for transmitting data between two devices.
Public Switched Telephone Network PSTN
A circuit-switched analogue network which makes connections for the duration of
telephone call. These connections are usually used for voice but can also carry
data between facsimile machines and computers (via a modem).
Redundancy
The ability of a system to continue non-stop when a failure occurs.
Router
The device that connects multiple computer networks by reading layer three
addressing on incoming and outgoing packets. Packet information is read and the
packets are then forwarded to the appropriate end station.
Satellites
A communication satellite can be thought of as a big microwave repeater in the
sky. A satellite dish is a broadband communication technology. It contains one
or more transponders each of which listens to some portion of the spectrum,
amplifies the incoming signal and then rebroadcasts at another frequency to
avoid interference with the incoming signal. The downward beam can be broad,
covering large areas (e.g. direct broadcasting) or narrow, focusing on a small
geographic area (e.g. pin pointing a ground station ). Satellites can also be
used for direct transmission between ground stations.
Server
A computer or device on a network that manages network resources. For example, a
file server is a computer and storage device dedicated to storing files. Any
user on the network can store files on the server. A print server is a computer
that manages one or more printers, and a network server is a computer that
manages network traffic. A database server is a computer system that processes
database queries.
Set top Box
A transmission/reception device that acts as an interface typically to a
television or other video output display device.
Signalling
The process of sending a transmission over a physical medium for purposes of
communication.
Synchronous Transmission
Data transmission using synchronization bytes, instead of start/stop bits, to
control the transmission.
T-1 Carrier
A dedicated phone connection supporting data rates of 1.544Mbits per second. A
T-1 line consists of 24 individual channels, each of which supports 64Kbits per
second. Each 64Kbit/second channel can be configured to carry voice or data
traffic.
Telco
A generic term for the local telephone company operator in a given area.
Telecommuting
American term for teleworking where people work from home either full time or as
part of their working week.
Terminal Adapter
A device that connects a computer to an external digital communications line,
such as an ISDN line. A terminal adapter is somewhat like a modem, but whereas a
modem needs to convert between analog and digital signals, a terminal adapter
only needs to pass along digital signals.
UPS
Abbreviation of uninterruptible power supply, a power supply that includes a
battery to maintain power in the event of a power outage. Typically, a UPS keeps
a computer running for several minutes after a power outage, enabling you to
save data that is in RAM and shut down the computer gracefully.
Videoconferencing
Allows two or more people to meet "face-to-face" as easily as dialling a
telephone call. A small camera captures the image of the users. Modern data
compression techniques allow this image together with high quality speech to be
carried in the two 64 kbps B- channels of an ISDN Basic Rate Access (BRA). For
three or more people to use this technology, a video conference "bridge" is
needed to switch the speed and images.
Video on Demand
The ability to activate a stored or live motion picture stream; in xDSL the
application that allows subscribers to view movies or other video programming on
request, similar to cable television's Pay-Per-View.
Voice Mail
Enables callers to leave a message much like an answerphone but this message can
then be reviewed, copied, stored, annotated and forwarded to one or many people
in one go. Sometimes called voice messaging.
Voice over IP
The ability to make calls and send faxes over IP-based data networks such
as the Internet, whilst simultaneously being online. It overcomes the problem of
tying up your only telephone line whilst browsing the web as calls can be made
at the same time.
VPN
Virtual private network is, a network that is constructed by using public wires
to connect nodes. For example, there are a number of systems that enable you to
create networks using the Internet as the medium for transporting data. These
systems use encryption and other security mechanisms to ensure that only
authorised users can access the network and that the data cannot be intercepted.
WAN
Wide area network is a computer network that spans a large geographic area.
Typically, a WAN consists of two or more local-area networks (LANs). Computers
connected to a wide-area network are often connected through public networks,
such as the telephone system. They can also be connected through leased lines or
satellites. The Internet is a good example of a large WAN.
WLL
Wireless Local Loop, another name for fixed wireless.
World wide web
Born out of the Internet, the World Wide Web is a collection of domains
throughout the world containing documents that are available for all and anyone
to view. Each domain has its own unique domain address, such as ours -
www.telehouse.net
X.25
X.25 is an internationally accepted protocol allowing terminals and
computers to be connected to a Packet Switched Data Network (PSDN).It is a way
to format information with an address and instructions, and allows a high degree
of connectivity. X.25 essentially specifies the format for transmitting data
between two devices.