BANDWIDTH The quantity of spectrum required for a specific purpose.

BLUETOOTH A short range wireless protocol meant to allow mobile devices to share information and applications.

BROADBAND NETWORKS Networks in which the bandwidth is split into multiple channels, enabling a number of simultaneous transmissions.

CDMA Code Division Multiple Access.

CO-LOCATION The ability for other operators to install equipment in BT's local exchanges in order to supply services over the local loop.

CPS Carrier Pre Selection.

DCS - 1800 Digital Cellular System at 1800 MHz.

DECT Digital European Cordless Telecommunications. A Europe-wide standard for digital mobile telephony, covering cordless PBXs, telepoints and home cordless telephony.

DiffServ Differentiated Services, or DS. A protocol for specifying and controlling network traffic by class so that certain types of traffic get precedence - for example, voice traffic, which requires a relatively uninterrupted flow of data, might get precedence over other kinds of traffic.

DWDM Dense Wavelength Division Multiplexing. Technology that puts data from different sources together on an optical fiber, with each signal carried on its own separate light wavelength.

E-1 European format for digital transmission. E-1 carries signals at 2.048 Mbps (32 channels at 64Kbps), versus the T-1, which carries signals at 1.544 Mbps (24 channels at 64Kbps). E-1 and T-1 lines may be interconnected for international use.

ECTRA European Telecommunications for Telecommunications Regulatory Affairs.

ETO European Telecommunications Office. A staffed office, located in Copenhagen, funded by ECTRA. It carries out and co-ordinates studies into European telecommunications matters on behalf of the EC and others and works in conjunction with ECTRA and its Project Teams.

ETSI European Telecommunications Standards Institute. Has the primary responsibility within Europe for the production of telecommunications standards for pan-European applification.

EXCHANGE A building equipped so that telephone lines (exchange lines) terminating there may be interconnected as required. Exchange lines are also known as trunk lines.

FACSIMILE (FAX) A system which provides a facility to transmit an exact copy of the image on a piece of paper form one location to another.

FCC Federal Communications Commission. The US regulatory body set up in 1934 to regulate all inter-state and foreign communications by wire, radio, television and radio. Intra-state communications are regulated by state public utilities commissions.

FDM Frequency-Division Multiplexing. Scheme in which numerous signals are combined for transmission on a single communications line or channel. Each signal is assigned a different frequency (subchannel) within the main channel.

FIXED WIRELESS The operation of wireless devices or systems in fixed locations such as homes and offices. Fixed wireless devices usually derives their electrical power from the utility mains, unlike mobile wireless or portable wireless which tend to be battery-powered.

FMI Fixed/mobile integration (also known as fixed mobile convergence). The merging of fixed and mobile services into an integrated service whereby the customer will be offered both fixed and mobile services and will receive one bill and/or receive and make calls using one terminal.

FRAME RELAY SERVICE A packet switched data service (see packet service) providing for the interconnection of Local Area Networks (LANS) and access to host computers at higher speeds (up to 2 Mbit/s) than those provided by an X.25 service.

FREEPHONE Automated reversed charge mechanism whereby caller pays nothing while company receiving call pays all call charges and associated costs (line rental, enhanced services).

GEOGRAPHIC NUMBER A number from the national numbering plan where part of its digit structure contains geographic significance used for routing calls to the physical location of the network termination point of the subscriber to whom the number has been assigned.

GPRS General Packet Radio Service.

GSM Global Standard for Mobile Telephony.

GSM 900/ 1800 MHz Global System for Mobile Communications in the 900 and 1800 MHz frequency bands.

HSCSD High Speed Circuit Switched Data is an enhancement of data services ("Circuit Switched Data - CSD) of all current GSM networks. It allows you to access nonvoice services at 3 times faster, which means subscribers are able to send and receive data from their portable computers at a speed of up to 28.8 kbps; this is currently being upgraded in many networks to rates of and up to 43.2 kbps.

HUBBING The routing of international traffic via an intermediate third country.

INTERCONNECTION The connection of separate telecommunication networks.

INTERNATIONAL PREFIX The combination of digits to be dialled, following access to the PSTN, by a caller making a call to a recipient in another country to obtain access to the automatic outgoing international equipment. For the UK, this prefix is "00".

INTERNET A global network of networks, mainly narrowband, accessed by users with a computer and a modem via a service provider.

INTEROPERABILITY The ability of different telecommunication networks and / or apparatus to work together to provide a seamless service for users.

IP Internet Protocol. Packet data protocol used for routing and carriage of messages across the internet.

ISDN Integrated Services Digital Network. A public network conforming to internationally agreed standards, fully integrating digital transmission systems with digital switching systems. ISDN allows the integration of multiple services -voice, data, fax etc - over a common network interface and can provide a wide range of network-based supplementary services such as CLI, Call Park, Call Diversion etc.

LATENCY The amount of time it takes a packet to travel from source to destination. Together, latency and bandwidth define the speed and capacity of a network.

LOCAL LOOP The local circuit connection between the customer and the customer’s nearest telephone exchange office.

NARROWBAND A service or connection allowing only a limited amount of information to be conveyed.

NDC National destination code. A code field within the ITU-T Recommendation E.164 numbering plan which combined with the caller's or called party's number (in ITU-T terms the subscriber's number (SN)) will constitute the national (significant) number of the international ISDN number. The NDC will have a network and/or trunk code selection function.

NATIONAL NUMBERING SCHEME A scheme for the allocation and re-allocation of numbers which is specified by the Director General and made available by him for public inspection.

NRA National Regulatory Authority. The body or bodies, legally distinct and functionally independent of the telecommunications organisations, charged by a Member State with the elaboration of, and supervision of compliance with, telecoms authorisations.

NETWORK OPERATOR The operator of a telecommunication network with a Public Telecommunications Operator (PTO) licence, which provides, amongst other things, network services.

NON-GEOGRAPHIC NUMBER These are numbers which are used to identify a type of service rather than a geographical location. These services are sometimes referred to as Specially Tariffed Services and include freephone, local rate, national rate and premium rate numbers. Mobile and Personal numbers are also non geographic numbers.

NUMBER PORTABILITY Number portability between operators enables a customer to transfer from one operator to a second operator and retain the same number provided the customer remains at the same address.

OPTICAL FIBRE Constructed using glass, and now fast replacing copper cables, as the medium of transmission of electronic information, particularly in high traffic applications. Unlike copper, optical fibre uses light pulses for transmission and can only transmit information in a digital form.

PABX or PBX Private (Automatic) Branch Exchange. Customer premises equipment (switch), which provides for the transmission of calls to and from the public telephone network.

PAGING A feature of a wireless device that allows reception of a signal or alphanumeric message.

PCN Personal Communications Network. The European digital cellular mobile telephone network, developed in accordance with GSM standards.

POP Point of Presence. The physical location within a LATA where an interexchange carrier's circuits interconnect with the local lines of telephone companies in that LATA.

PRS Premium Rate Service. Services, including recorded information and live conversation, run by independent service providers. All calls to these companies are charged at a higher rate than ordinary calls to cover the companies' costs in providing the content of the call and the operator's cost for the special network facilities needed.

PRIVATE CIRCUIT A telecommunication link provided by a network operator for the exclusive use of the customer.

PRIVATE NETWORKS A telecommunications network on the customer's side of a network termination point, which forms the boundary between a public telecommunication system run under a PTO licence and the user's network, generally run under a Class Licence.

PSTN Public Switched Telephone Network. The complete network of interconnections between telephone subscribers, operated for public use by one of the licensed PTOs.

PTO Public Telecommunications Operator. Major operators who are so designated by the Secretary of State for Trade and Industry.

ROAMING Using your wireless phone in an area outside its home coverage area. There is usually an additional charge for roaming.

SDH Synchronous Digital Hierarchy. A standard technology for synchronous data transmission on optical media.

SNA Proprietary IBM architecture and set of implementing products for network computing within an enterprise . It existed prior to and became part of IBM's Systems Application Architecture (Systems Application Architechture) and it is currently part of IBM's Open Blueprint.

SONET Synchronous Optical Network. U.S. standard for synchronous data transmission on optical media. The international equivalent of SONET is synchronous digital hierarchy (SDH).

TDM Time-division multiplexing. A process whereby a number of different channels can be transmitted over a common circuit by allocating the circuit to each channel in turn for a given period of time.

TDMA Time-division multiple access.

THIRD GENERATION (3G) means, for the purposes of this Condition spectrum within the 1900–1980 MHz, 2110–2170 MHz.

UMTS Universal Mobile Telecommunications System. So called 3rd generation mobile communications system which will provide enhanced range of multimedia services (eg. video, high speed internet access).

VOICE MAIL Facility to leave a voice message which can be accessed from different locations.

VoIP Voice over IP. Voice communications transmitted over the Internet.

VPN Virtual Private Network.

WAP Wireless Application Protocol.

W-CDMA Wideband Code Division Multiple Access.

WLL Wireless Local Loop. A wireless system meant to bypass a local landline telephone system. A home or businesses phone system is connected to the public network by a wireless carrier instead of by the traditional local phone company.

xDSL Variety of new Digital Subscriber Line technologies. Some of these varieties are asymmetric with different data rates in the downstream and upstream directions. Others are symmetric. Downstream speeds range from 384 kbps (or "SDSL") to 1.5-8 Mbps (or "ADSL").