Glossary - The Explanations

Below is a list of terms used on this site and their meanings. Click on the term in the box on the right to jump to the explanation.


Activation is the term used to describe the process by which your existing phone line becomes enabled to receive data and voice calls simultaneously. The activation takes place at your local phone exchange.


Asymmetric Digital Subscriber Line. ADSL is a technology that transforms a standard twisted pair of copper wires telephone line into a high-speed always on, internet connection capable of simultaneously carrying voice and data. It is termed 'asymmetric' because data moves in one direction faster than in the other i.e. it is quicker to download rather than upload data as data is transmitted faster from the exchange to you rather than from your premises to the exchange.

Anti-virus software

Protection against malicious computer code usually sent via email but sometimes infecting web site downloads. PCs are particularly vulnerable and you should have anti-virus software installed no matter which way you connect to the internet.


Application Service Provider. A company that rents access to software and services across the internet. This means that businesses can use services such as payroll and time sheets without having to invest in the software and equipment required to run them.


The capacity of your internet connection to transmit and receive data. Bandwidth is usually measured in bits-per-second. Imagine your internet connection is a pipe, the bigger the pipe, the faster the information will flow. Broadband offers speeds between 10 and 40 times faster than a 56K dial up modem.


A generic term for high speed digital internet connections.


Bursts of data traffic generated by a computer while online. Web browsing and reading email are 'bursty' activities. Downloading software or a bulky document generates a longer constant demand on bandwidth and is therefore non-bursty. A high number of users can share the same bandwidth with little loss of speed if their data calls are bursty.

Contention Ratio

This describes the maximum number of users sharing the bandwidth on the connection between your local exchange and the Internet Service Provider. A customer with a contention ratio of 20:1 never has to share this bandwidth with more than 19 other users.


Digital Subscriber Line Access Multiplexer. Kit in a local exchange that aggregates the connections of broadband users into one or more link onto the main internet infrastructure.

Dynamic IP Address

Originally all Internet Protocol addresses were static, but with the growth of the internet it soon became clear there wouldn't be enough to go around. A dynamic IP address changes every time you connect to the internet. Your ISP will have a range of dynamic IP addresses available and you will be allocated any one of these at any time.


A means of codifying information to prevent unauthorised access. Only those with authorisation and the key to unlock the code can decipher the encrypted data.


Ethernet is the most widely-installed local area network (LAN) technology. Most new computers have this capability pre-installed or can be upgraded to take advantage of this connection method.


An intranet that is accessible to computers that are not physically part of a company's own private network, but that is not accessible to the general public. For example, to allow vendors and business partners to access a company web site.


Gatekeeper hardware or software that guards against unauthorised access to your computer via the internet by hackers.

Gateway Address

The IP address you use when you make a connection outside your immediate network.


Configuring your computer system to the fast lane of the information super highway. There are normally two options available:


A private network or web site for internal company or organisation use. Can be tunneled into by authorised users.

IP Address

Stands for Internet Protocol address, the host computer assigned to you by your Internet Service Provider when you make a connection. A static IP address means your ISP permanently assigns your connection to a particular host computer. IP addresses are numeric, you may have noticed them occasionally in the address bar of your browser. For example, is better known as An internet service called DNS (Domain Name System/Service) translates the request for into the corresponding IP address.


Internet Service Provider. Typically this refers to the company supplying your connectivity to the internet. For example BT Openworld or Eclipse.


Kilobits per second (1 kilobit per second equals 1,000 bits per second). A measure of data transfer through a modem or on a network.


Local Area Network. Normally refers to a network confined to a single defined area, usually the same floor or building.

Login or Logon

The method by which you identify yourself to a host computer or website. This often means typing in a user name and password.



Megabits per second. A unit of bandwidth measurement that defines the speed at which information can be transferred through a network or Ethernet cable. One megabyte is roughly equivalent to eight megabits.


A channel splitter that inserts into the phone socket to prevent noise interference from an ADSL connection on phone extensions during voice or fax calls.


Network Address Translation. A broadband configuration that offers extra security and enables more than one computer to use a single IP address (your location on the internet).

Network Adapter

Also known as a "network interface card" (NIC). An expansion card or other device used to provide network access to a computer, printer, or other device.


If you need someone or something (such as a server) that is outside of your network to connect to a machine inside your network, then you need non-NAT. The non-NAT option offers extra IP addresses and routes data to specific addresses.


A unit of information transmitted as a whole from one device to another on a network.

Peer-to-Peer Network

A network of two or more computers that communicate without using a central server. This lack of reliance on a server differentiates a peer-to-peer network from a client/server network.


A method of bouncing a signal to a computer's IP address to check if it is online and to measure the response time. Rather like radar or echo location on a submarine.

Remote Working

The ability to access your own computer securely across the internet. Requires your machine to be connected to a static IP address.

RJ-11 Connector

Cable connection for joining a phone line to a modem.


Small square-ish plug found at the ends of Ethernet cables.


A device that sits between your computer and the internet and determines where to send your online data. Often used when more than one computer is sharing a connection. Also known as a gateway or base station.

Satellite Broadband

Broadband connectivity supplied from a satellite located in geostationary orbit.


Symmetric Digital Subscriber Line, a broadband variant that offers equal or near equal bandwidth up and downstream using DSL technology.

Static IP Address

A static Internet Protocol address that doesn't change every time you log on to the Internet. A static IP address is required if you need to run your own email server (SMTP), Virtual Private Network or remote communications applications.

Two-Way Satellite

Broadband connection whereby the upstream (outbound) and the downstream (inbound) data are sent from and arrive via a satellite. The connection is usually asymmetric, i.e. the download speed is faster than the upload speed. One way satellite is when the upstream traffic is routed terrestrially, normally via a dial up modem.

Unified Messaging

Provides one centralised in-box for all voice, email and fax messages. All message types can be managed using familiar packages such as Microsoft Outlook or Lotus Notes.

Video Conferencing

Real time video, to allow multiple users to broadcast and receive sound and vision simultaneously.

Virtual Server

A web server that hosts a number of sites simultaneously, each with a unique domain name and IP address.

Virtual Private Network

Virtual Private Network. This allows a secure, encrypted connection between two points over the Internet.

Voice Over Internet Protocol (VoIP)

Using broadband to send voice calls over the internet. The voice signals are broken down into packets and reassembled at the receiving end.


Wide Area Network. A geographically widespread network that might include many linked local area networks.


Wired Equivalent Privacy. WEP sometimes also goes under the alias of "wireless security". Essentially wireless network encryption to protect data transmitted over wireless networks.


Commonly used to signify the 802.11b standard - a form of wireless networking. Wireless-Fidelty allows the connection of two or more computers without the need for physical cabling between them. The most common forms of WiFi are 80211.b (capable of up to 11 Mb/Sec) and 802.11.g (capable of up to54 Mb/Sec).


The use of radio signals to connect computers without cables whether it be a computer and a mouse or a network of computers that connect to the internet.

Wireless Access Point

A device that exchanges data between wireless computers or between wireless computers and wired computers on a network.

Wireless Network Name

Single identity for a group of computers that link together to form a wireless network.

Wireless WAN

Companies with more than one building on a campus or in close proximity in a city centre can use Wi-Fi or other wireless technology to build 'bridges' between buildings.


Wireless local area network. A network that exclusively relies on wireless technology for device connections.