Our guide to the small print

Control energy costs, smart meters, Digital smart meter, Bolton, Manchester, Birmingham


ADSL – Asymmetrical Digital Subscriber Line. This is, technology that enables faster data transmission over copper telephone lines than a conventional voice band modem can provide. You can also use these lines for simultaneous voice and data transmission

Analogue Line – . these are the original lines used for making telephone calls. It commonly refers to a single line from your house/office to the point at which the line connects to the main telephone network (PSTN). It is cheap and reliable but lacking in features that businesses now take for granted.

Bandwidth – this is the the maximum amount of information (bits/second) that can be transmitted along a channel

Bluetooth – this is a short-range wireless technology designed to allow connection of portable devices in a wire-free manner.

Broadband – this is the data communications method of sending multiple bits of data simultaneously down the same line to give a high throughput or bandwidth.

DECT –Digitally Enhanced Cordless Telephone. DECT is the standard for cordless telephones. DECT phones communicate using the PSTN (public switched telephone network) through a small base station in the home or office and have a working radius of between 50 and 300 meters

FCT – Fixed Cellular Terminal. This is a mobile device that allows fixed telephony devices such as PBX Telephone Systems to connect directly to the GSM Mobile Phone Network – This may be to allow PBX users to call colleagues on their mobiles free of charge, or call other mobile users at reduced rates (depending upon available tariffs)

ISDN – Integrated Services Digital Network, this refers to an international standard for sending voice, video and data over telephone wires. ISDN lines are different to standard analogue lines in that they are specifically designed to carry multiple simultaneous voice calls and data, generally for video conferencing. It is available in two main derivatives; ISDN 2 and ISDN 30. ISDN benefits over analogue or ordinary telephone lines in several ways; it dials and connects quicker (1-3 seconds) and supports multiple telephone numbers per line.

LCR  – Least-Cost Routing. This generally refers to the process where an end user will pay BT for their line rental, but will use a cheaper carrier for their calls. The end user would dial a call prefix which tells the local exchange which carrier is being used instead of BT (this can be done call by call, or more commonly is handled automatically by the office phone system) .

LLU – Local Loop Unbundling.  This is the process where communications providers other than BT can take control of individual lines within the BT network. They can then route calls over their own networks. They can also bill directly for line rental instead of the customer having to receive two bills (one for line rental and one for calls)

PABX – Private Automatic Branch eXchange. This generally refers to a phone system consisting of multiple handsets and a central automated switchboard. Inbound calls can be automatically directed to the correct user by number dialled, generally a DDI. Users can dial each other internally by dialling a short ‘extension’ number and the outside world can be dialled by prefixing a call with a number normally 9 or 0

PSTN – Public Switched Telephone Network. This refers to the legacy infrastructure traditionally used to carry most telephone calls. It includes all the lines and cables from the connection point in your home or office, out of your building to the overhead phone lines, through to localised boxes you see at the end of the road to the local exchange and onwards nationally and internationally. It started off as an analogue system but is now almost completely digital.

Resilience – this is the ability to provide and maintain an acceptable level of service in the face of faults and challenges to normal operation

SDSL – Symmetrical Digital Subscriber Line.  This is the technology that enables quick transmission of data over standard telephone lines. It is commonly used as a cost effective method to provide internet access and company networks across multiple offices. It is symmetric as the download and upload speeds are the same.

SIP – Session Initiation Protocol. This specifically refers to a standard protocol used for initiating and terminating video and voice calls over an IP network. This is an open standard that the majority of VoIP or Internet Telephony providers adhere to.

VoIP – Voice over Internet Protocol. This is one of the names for the technology that uses an IP network, such as the internet, to carry part or all of a phone call. One of the main benefits is that a user can make or receive calls wherever they can get an Internet connection, plus it offers a far greater range of functionality and a much cheaper price than traditional PABX style systems.

VPN – Virtual Private Network. This is a secure network that is used by companies (and individuals) to communicate confidentially over public networks such as the internet. Common users of this technology are remote/home workers who need to access their company’s central systems.

WAN – Wide Area Network. This is a computer network that covers a large geographic area. This could be a company joining their offices together in different cities or the Internet which is world wide