Glossary of terms


ADSL: Asymmetric Digital Subscriber Line – A technology for the delivery of digital data over existing twisted pair copper subscriber lines. (Normal phone lines). The analogue telephone service shares the copper with ADSL signals. The data rate is asymmetric. This means that the downstream rates are significantly faster than the upstream rates.


Basic Access Lines: Local access connection between a customer’s premises and a carriers local switch.

Blue Tooth: A very low powered consumer electronics standard being supported by many vendors as a standard way of connecting consumer electronics without cables.

bps: bits per second
A measure of data speed for transmission carriers. The speed in bps is equal to the number of bits transmitted or received each second.

Broadband: This is a generic term for high bandwidth capacity internet. Any internet service with the capacity to deliver digital data at hundreds or thousands of bits per second would be considered broadband.


CAN: Customer Access Network – The customer end of the telephone network. The CAN is the part of the telephone network that allows telephone users to connect to connect to the local switch or exchange. It is also known as the local loop and largely consists of pairs of twisted copper wires.

Carriage Service Provider: This is an organisation that provides a telecommunications service to the public using carrier network infrastructure.

Carrier: The holder of a telecommunications carrier licence in force under the telecommunications act 1997. The provider of telephone services to the customer.

CDMA: Code Division Multiple Access – A sophisticated spread spectrum technique that can be used in a variety of wireless delivered services, including mobile phones. CDMA employs a bandwidth much larger than the original signal. Each signal is uniquely encoded and decoded and allows many signals to occupy the same spectrum.

CIR: Committed Information Rate – Commonly used in Frame Relay for a data rate the customer wants always available and is prepared to pay for.
Circuit Switching: When a call is made between two parties, the connection is maintained for the entire duration of the call. Connecting two points in both directions, the connection is called a circuit. This is the foundation of the PSTN.

CLI: Calling Line Identification – This identifies the number of the calling party’s line.

CND: Calling Number Display – A telephone feature which displays the caller’s number.

CNI: Calling Number Identification as in CND.

CPE: Customer Premises Equipment – End- User equipment that is located on the customer’s premises or physical site location rather than the provider’s premises or elsewhere on the network. Telephone handsets, modems and personal computers are all examples of CPE.

CPU: Central Processor Unit – Central Processor of a computer or exchange.


DECT: Digital Enhanced Cordless Telecommunications – A technology for short range cordless telephony in environments where there are large numbers of users, such as offices.

Dial – Up: In the context of internet use, it refers to using the telephone network to dial up a link to an internet service provider (ISP). The link to the ISP is only maintained for the duration of the connection.

Digital Compression: Technology which dramatically decreases the bandwidth requirements for data-rich multimedia signals, which ultimately lowers the cost of digital transmission.

DNS: Domain Name Server – Resolves names and IP addresses. DNS servers in the internet implement a hierarchical name space that allows sites freedom in assigning machine names and addresses.

DSL: Digital Subscriber Line.

DSLAM: Digital Subscriber Line Access Multiplexer – A network device located in a telephone exchange that receives signals from multiple customer Digital Subscriber Line connections and puts the signal on a high speed backbone line using multiplexing techniques.


ETSI: European Technical Standards Institute.

Exchange: Network node where various numbers and types of communication lines are switched by the telecommunications user or network operator. Exchanges operate at local, trunk and international levels.


Fibre Optics: A means of transmitting digital information over a glass strand of fibre. Laser light pulses are sent over the glass signals. Though only as thick as human hair, each fibre optic strand has far greater capacity or bandwidth to carry information than copper wire.

Firewalls: Firewalls sit between the internal network (LAN) and the external (internet) network. Their purpose is to shield the network from unwanted entry. They monitor packets and addresses of passing traffic and may pass or block certain addresses or transaction types as a security management tool.

Frame Relay: A telecommunication service designed for data transmission for intermittent traffic between local area networks and between endpoints in a wide area network. Frame relay puts data in variable size unit called a frame and leaves any necessary error correction up to the end points, thus speeding up the overall data transmission.

FTP: File Transfer Protocol – Process for downloading large computer files from the internet


Gbps: Gigabits per second – One thousand million bits per second.

GHz: Gigahertz – One billion hertz.

GSM: Global System for Mobile Telephony. – This is the mobile technology originally selected to replace analogue and capable of providing enhanced features and data transmission.

GPRS: General Packet Radio Standard. – Satellite based positioning systems where GPS satellites send out reference signals that can be detected and used to calculate position and height.


HDSL: High Capacity Digital Subscriber Line – This is a symmetric version of DSL, with equal amount of bandwidth available in both directions.
For this reason the maximum data rate is lower than for ADSL.

Hertz (Hz): Rate of frequency in cycles per second, used to measure sound, electricity and radio signals.


IAP: Internet Access Provider – A wholesaler of internet bandwidth and related services to ISPs.