Glossary

ADSL - stands for Asymmetric Digital Subscriber Line. ADSL supports data rates from 500kbps up to 24mbps when receiving data and when sending data at speeds of 16k to 650k a second. To use ADSL you need to have a special ADSL modem and your telephone exchange needs to be ADSL enabled.

ISDN - Integrated Services Digital Network - a set of communications standards offered by telephone carriers which provides users with fast Internet connections.

LAN - A computer network that spans a relatively small area. Most LANs are confined to a single building or group of buildings. However, one LAN can be connected to other LANs over any distance via telephone lines and radio waves. A system of LANs connected in this way is called a wide-area network (WAN).

Most LANs connect workstations and personal computers. Each node (individual computer ) in a LAN has its own CPU with which it executes programs, but it also is able to access data and devices anywhere on the LAN. This means that many users can share expensive devices, such as laser printers, as well as data. Users can also use the LAN to communicate with each other, by sending e-mail or engaging in chat sessions.

MEGABYTE - A measure of storage space. 1 Mb roughly translates to a million characters of text, or 180,000 words.

OPERATING SYSTEM - The operating system or OS is a program, or a collection of programs, that manages all your computer's resources - disk drives, RAM, display screen - and controls how files are stored and retrieved.

ROUTER - A router is an Intermediate System (IS) which operates at the network layer of the OSI reference model. Routers may be used to connect two or more IP networks, or an IP network to an internet connection.

VPN - Short for virtual private network, 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 authorized users can access the network and that the data cannot be intercepted.

WAN - A computer network that spans a relatively large geographical 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 largest WAN in existence is the Internet.