A base station in a wireless LAN. Access points are typically stand-alone devices that plug into an Ethernet hub or server. Like a cellular phone system, users can roam around with their mobile devices and be handed off from one access point to the other.

Asymmetric Digital Subscriber Line. A DSL, or Digital Subscriber Line, commonly transfers data to and from a subscribers premises by 'piggybacking' onto existing infrastructure, most commonly a standard analogue BT telephone line. Existing mains power supply cabling is sometimes utilized, also satellite or proprietary cabled networks. The data transfer is carried out by means of a high-frequency 'carrier' which does not interrupt the normal working of the existing service used as the vehicle for transmission. Data transfer is divided into two components - transmission and reception. In Asymmetric transfer (ADSL), one (usually transmission) is carried out at a slower rate than the other.

A new technology designed to be embedded in electronic devices in order to provide wireless and seamless connections over short distances. The idea is to provide an easier to use alternative to the cable-based interfaces currently in use to link computers and computer peripherals. Other devices in which Bluetooth chips could be embedded include mobile telephones, personal digital assistants, headsets and wristwatches.

A term applied to telecommunications systems capable of simultaneously supporting multiple information formats at relatively high speeds such as voice, high-speed data services and video services on demand. Overall transmission speeds are typically hundreds to thousands of times faster than those of Narrowband systems.

A digital network feature where identity information from the device making a call is interpreted by the device answering the call. This is usually given in that the form of the telephone number of the person who is calling you.

A service provided by a PTO which uses the local telephone exchange to provide PBX facilities at the customer premises.

Call Information Logging Equipment.

Means of creating telecoms connections by setting up an end-to-end circuit. The circuit remains open for the duration of the communication and a fixed share of network resources is tied up with no one else able to make use of them until the connection is closed. The main advantage of circuit-switching is that it enables performance guarantees to be offered. See also Packet Switching.

The combination of PBX features allowed for a particular extension or group of extensions.

It is based on that the ability of the telephone system and computer to exchange information. One example of an application is the ability to present on screen information such as scripts, simultaneously with an incoming call. The scripts are based upon information gathered about the caller prior to the telephone being answered. This is generally achieved by either menu systems or by an identification are of the incoming line which the caller has dialed or his calling line identity.

Direct Exchange Line.

The ability to identify the number to which the call was made. In a call centre, for example the call may come into a specific DDI number. The call is answered by an agent in an ACD group, and the system uses the DNIS to present the agent with a screen containing a script associated with that DDI number.

DDI uses a small group of exchange lines to access a larger number of extensions. The first part of the number selects the line, whilst the last part gives the extension number. This method is very economical on exchange lines.

Dual Tone Multi Frequency See also MF.

The most widely-installed LAN technology. Standardized as IEEE 802.3, an Ethernet LAN uses Carrier Sense Multiple Access with Collision Detection (CSMA/CD) protocol (originally developed to manage radio based data communications - hence the name Ethernet) running over a coaxial cable or twisted pair wires. The most commonly installed Ethernet systems are called 10BASE-T and provide transmission speeds up to 10 Mbps. Fast Ethernet, or 100BASE-T10, provides transmission speeds of up to 100 Mbps and is typically used for LAN backbone systems, supporting workstations with 10BASE-T cards. Gigabit Ethernet provides an even higher level of backbone support at 1 Gbps.

High speed transmission method, switching packets of data through its network to their destination. Access to the network is via Frame Relay Access Devices (FRADs) which translate the data (eg Ethernet, Token Ring) into frame relay packets. The network sets up a virtual circuit which is a path to the destination. Frame relay is more popular in the US than in Europe, but the main European carriers offer frame relay service. Frame relay can operate at speeds of up to 45 Mbps, since it is a lightweight system without error correction, relying on the integrity of the fiber optic hardware.

A fully digital telecommunications network access method which works over copper wires. There are two types of ISDN, basic rate and primary rate. Basic rate ISDN provides subscribers with two 64 kbps information channels and a single 16 kbps control channel. Primary rate provides users with thirty 64 kbps information channels and a 64 kbps control channel.

The device which can interpret and react to voice or tone commands.

A world-wide network of computer networks in which users at any one computer can, if they have permission, get information from any other computer. The idea was conceived by the Advanced Research Projects Agency (ARPA) of the US government in 1969 and was first known as Arpanet.

Point of access to the Internet for small business and individual users. The ISP provides its customers with dial-up access to its router which relays traffic to web servers on the Internet.

Also known as Internet Telephony or Voice over IP (VoIP). Use of Internet Protocol (IP, see TCP/IP) to carry and route two-way voice communications. IP Telephony can support telephone to telephone links through suitable adapters but also voice communications from telephone to IP terminal (such as a PC with sound card) or from IP terminal to IP terminal. The technique promises drastically reduced costs to carriers and therefore prices to end users.

Integrated Services Digital Network.

Kilobits Per Second a measure of the speed of data capable of passing along a line expressed in thousands of bits.

The frame on which incoming cables from a PTO are terminated.

A measure of the speed of data capable of passing along a line expressed in millions of bits.

Abbreviation of modular/demodulator, the modem converts digital computer signals into analogue form for transmission over analogue telephone systems. Modems work in pairs, so at the other end of the channel the signal is returned to digital form. Remember, traditional telephone networks were designed for the human voice, which are analogue, not digital computers.

A method of dialing using combinations of tones to denote different numbers. Widely used on PABX's, but now also used between PABX's or DELs and electronic public exchanges. Also known as MF4.

A network is a collection of computers all linked together to share data. Classified according to their geographical extent: LAN (local area network); WAN (wide area network). LANs may be interconnected through WAN connections.

The method used to move data on the Internet. In a packet switching network, all the data coming from a machine is broken up into chunks. Each chunk includes the addresses of both the origin and the destination. This enables chunks of data from many different sources to intermingle on the same lines and be sorted and directed along different routes. In this way, many people can use the same lines at the same time.

Now frequently known simply as PBX. A privately operated switching system with exchange lines to a public telecommunications system (e.g. BT or Mercury Networks) and capable of having an operator console connected to it. The term was originally devised to differentiate the PABX from the PMBX. It is now being superseded by the term PBX.

Public Switched Telephone Network.

Public Telecommunications Operator (e.g., Cable & Wireless or BT).

A technique of encoding analogue voice signals into digital form.

A device which automatically answers a line and delivers a pre-recorded message. Often used to tell a caller that they are in a queue and will be dealt with as soon as possible.

A feature on PBX phones allowing users to dial programmed numbers by simply pressing one button (or entering a two or three digit code).

Collective name for the set of protocols on which the Internet is based. TCP and IP are the best known of this set, but they are by no means the only ones. TCP guarantees that every byte sent from one port arrives at the other in the same order and without duplication or loss. IP assigns local IP addresses to physical network addresses providing a structure which can be recognized by Routers. Other members of the TCP/IP family include the Telnet protocol which allows a remote terminal to log in to another host, the Domain Name System (DNS) which allows users to refer to hosts by name rather than having to know their numeric IP addresses, the File Transfer Protocol (FTP) which defines a mechanism for storing and retrieving files, and Hypertext Transfer Protocol (HTTP) which allows information to be transferred from host computers to computers equipped with web browsers.

Equipment providing no break power supply for the duration of the reserves of its batteries in the event of failure of the primary source of power.

Looks for all intents and purposes like a private network but is actually just access to a shared network. Careful management and guarantees of quality of service levels ensure that corporate customers get the privacy and facilities they want but at a lower cost.

See IP Telephony.

WAP was jointly developed in 1999 in the mainstream of Internet standardization activities, with the broad support of many vendors. It provides the basis for a whole host of new wireless information applications by offering a gateway between the Internet and mobile telephones. If an application can be put on the Internet, it can be made available to mobile terminal users through WAP.