Mobile Phones Glossary

Airtime
Actual time spent talking on the cellular telephone. Most carriers bill customers based on how many minutes of airtime they use each month. Airtime charges during peak periods of the day vary from about 20 cents to more than 40 cents per minute, depending on the service plan selected. Most carriers offer reduced rates for off-peak usage.

Airtime provider
A company that sells you services provided by BT Cellnet or Vodafone. Airtime providers were instigated by the government to promote competition in the early days of mobile phones. Orange and One 2 One, however, have been allowed to sell services direct to the public.

AMPS
Advanced Mobile Phone Standard. Analogue standard used widely in North America.

Alphanumeric
A message or other type of readout containing both letters ("alphas") and numbers ("numerics"). In cellular, "alphanumeric memory dial" is a special type of dial-from-memory option that displays both the name of the individual and that individual's phone number on the mobile phone handset. The name also can be recalled by using the letters on the phone keypad. By contrast, standard memory dial recalls numbers from number-only locations.

Analogue
The traditional method of modulating radio signals so that they can carry information. AM (amplitude modulation) and FM (frequency modulation) are the two most common methods of analog modulation. The UK’s last analogue mobile phone network is due to close down in summer 2001.

Authentication
A fraud prevention technology used by Vodaphone that takes a number of values to create a shared, secret value used to verify a user's authenticity.

Bluetooth
A specification for short-range wireless connectivity that allows users to make wire-free connections (via radio link) between a wide range of communications devices.

Caller display
System found on digital mobile phones whereby the number of an incoming caller is displayed on-screen before the phone is answered. The service is also available on fixed phones, but requires a special phone or add-on display unit, and necessitates paying BT an additional quarterly fee.

Call screening
Facility on some answering machines that allows the user to hear who’s calling so they can decide whether to answer in person or not.

CDMA
Code Division Multiple Access: Digital cellular standard used in Japan, parts of the Far East and parts of the USA. Uses coding of digital segments of calls to enable them to use vacant channels over a broad range of frequencies.

Cell broadcast
Service provided by digital cellphone networks where useful info is provided to users via on-screen text messages. Currently used by Vodafone and BT Cellnet to inform customers of the STD code of the area they are currently located – enabling them to take full advantage of local call discount schemes.

Cellular
A radio phone system in which a network of transmitters links the mobile user to the public phone system. Each transmitter covers users in its own ‘cell’.

CLI
Calling Line Identification. A range of services in which the number of a caller can be accessed by the recipient. The 1471 service offered free to BT customers is one of these – as is the caller display service provided to digital cellphone users.

Clone
Whereby a ‘cloned’ analogue cellphone is illegally re-chipped with an ESN belonging to another. Can also refer to a phone ‘badged’ by one company and sourced from another.

Coverage
The area in which a cellphone can make or receive calls. Coverage is usually expressed by networks as a percentage of the resident population who could use mobiles outside their own homes. Geographic coverage, therefore, is far inferior to this ‘by population’ figure.

CT0
The standard used by first-generation cordless phones. This analogue system can make use of just eight channels (some phones use only one), which can lead to problems with interference, particularly in built-up areas.

DCS1800
A digital cellular system operating in the 1800MHz band. Another name for PCN or GSM1800 networks.

DECT
Digital Enhanced Cordless Telecommunication. Digital standard for cordless phones. Using 120 channels over 10 frequencies, these cordless phones offer speech quality which is vastly superior to that offered by traditional (CT0) analogue cordless phones.

Desktop charger
Cradle for holding a phone upright while it is charging.

Digital
A method of decoding information for transmission. Information, or in this case, a voice conversation is turned into a series of digital bits - the 0s and 1s of computer binary language. At the receiving end, the information is reconverted. One of the main advantages of digital cellphones is that they allow several cellphones in the same area to use the same frequency simultaneously.

DTMF
Facility for sending multi-frequency tones across the network from a phone. Each number, when pressed, transmits its own individual sound. Necessary for accessing some network features (such as voicemail) or for some information services.

DTX
Discontinuous transmission. Battery-saving feature on some phones. When switched on, it conserves power by turning off transmission during pauses in speech. However, it impairs sound quality.

Dual-band
Phones that can switch between two different bands of frequencies. All new phones in the UK are now dual-band, capable of switching between GSM1800 and GSM900 frequencies. Useful for travellers (particularly those on One 2 One and Orange), allowing roaming on a greater number of networks across the world. Vodafone and BT Cellnet also utilise dual-band capabilities in the UK by using 1800MHz bandwidth to solve capacity problems on their 900MHz networks. Phones that can switch between GSM900 and GSM1900 operation, for use by travellers to America (the Bosch World 718, Ericsson I888 and Ericsson T28 World), are also now available.

Dual-mode
Phone that can operate using two different standards. Dual-mode digital/analogue cellphones are currently available in the USA. Dual-mode GSM/DECT handsets, that can switch between cordless and cellphone communication, have been introduced by BT Cellnet and Sagem.

Emission category
The more powerful the transmitter in your cellphone, the better it will be in giving you coverage in remote areas. Hand portable phones are Class 4 devices (as defined by the DTI) and offer maximum output of 2 Watts (although this is usually limited to 0.6 Watts). Carphones and transportables are usually Class 2 devices offering a maximum signal output of 8 Watts.

ESN
Each cellular phone is assigned a unique ESN, which is automatically transmitted to the cellular tower station every time a cellular call is placed.

ETACS
Extended Total Access Communications System. The standard used by UK analogue cellphones. Originally termed TACS, additional frequencies were added to increase network capacity.

ETSI
European Telecommunications Standards Institute. The people who wrote the specification for GSM and DECT.

GPRS
General Packet Radio Service. Data communications upgrade for GSM networks, enabling a maximum data rate of up to 115kbps. All UK networks are aiming to adopt this system by early 2001.

GSM
Global System for Mobile Communications. A digital cellular communications standard used throughout Europe, and elsewhere around the world. The standard is used in three frequency bands – 900MHz, 1800MHz, and 1900MHz. In the UK, the term GSM is commonly used to mean GSM900 – while GSM1800 networks are often referred to as PCNs.

GSM900
GSM network operating in the 900MHz band – as used by BT Cellnet and Vodafone in the UK, and by more than 100 countries around the world.

GSM1800
GSM network operating in the 1800MHz band – as used by Orange and One 2 One in the UK, and by a small but growing number of countries around the world.

GSM1900
GSM network operating in the 1900 MHz band – as used in several states in the USA plus parts of Canada and South America.

Hand-over
As you move, the network transfers the handling of a call from one cell to another. The process happens automatically.

Hands-free
An important safety feature that's included with most of today's mobile phones. It permits drivers to use their cellular phone without lifting or holding the hand-set to their ear. Available as an accessory for most mobile phones.

HSCSD
High Speed Circuit Switched Data. An enhancement to GSM networks that enables data speeds to be boosted from 9.6kbps in multiples up to 57.6kbps, by combining timeslots. Orange has begun to use HSCSD for certain services.

IMEI
International Mobile Equipment Identity. A unique serial number used on digital mobile phones.

IMT-2000
International Mobile Telecommunications-2000. The ITU’s concept of a ‘family’ of compatible third generation mobile technologies. UMTS is the European member of the IMT-2000 ‘family’.

ISDN
Integrated Services Digital Network. High quality fixed telephone line used primarily for data transfer between companies or for video conferencing.

ITU
International Telecommunications Union. Geneva-based organisation within which governments and the private sector co-ordinate global telecom networks and services.

LAN
Local Area Network. Communications system used by offices that connects computers to their servers, and allows employees to share files and printers.

Mobile Phone
Also known as a car phone - the type of cellular phone that's installed in a car, truck or van. There are three main types of cellular phones being sold today: mobile, transportable and portable. A mobile unit is attached to the vehicle, draws its power from the vehicle's battery and has an external antenna.

Off Peak
The period of time after the business day has ended during which carriers may offer reduced airtime charges.

OFTEL
The Office of Telecommunications. Independent watchdog for the UK telephone and mobile industry.

OGM
Outgoing message. What the caller hears when they dial your answer machine or voice-mail box.

One-touch memory
Button on a phone that allows you to dial a number just by pressing this one key. Also known as a fastkey.

PABX
Private Automatic Branch Exchange. Automated multi-extension exchanges or switchboards as used nowadays by most offices.

Peak
Highest-usage period of the business day when a cellular system carries the most calling traffic.

Pre-pay/Pay-as-you-go
Term used for no-contract, no rental charge services where you buy credit ‘vouchers’ in advance for calls. Each network has its own pre-pay service.

PBX
Private Branch Exchange. Multi-line switchboard exchange, as used in many offices.

PC card
Small accessory that allows you to connect a suitable digital mobile phone with a portable computer. Primarily designed for sending and receiving faxes and digital files (such as email).

PCMCIA card
An older term for the PC card.

PCN
Personal Communications Network. Another term for a GSM1800 network – such as Orange or One 2 One.

PCS1900
Personal Communications System operating in the 1900MHz band. Another name for GSM1900.

PDA
Personal Digital Assistant. A top-of-the-range personal organiser which allows you to store information and to use simple computer programs – as made by companies such as Psion. Also known as a palmtop computer. The Nokia 9110 Communicator is a PDA with a built-in mobile phone.

PMR
Private Mobile Radio. Type of mobile and walkie-talkie equipment commonly used by taxi firms, security guards, and utility companies. The advantage over cellphones is that once the equipment is paid for, and a licence is bought, there are no call costs.

Portable
A one-piece, self-contained cellular telephone. The newest portable model phones are so small - weighing as little as 3.1 ounces - that they can be folded up and carried in a suit pocket or purse. Portables normally have built-in antennas and a rechargeable battery. See also Mobile and Transportable.

PSTN
Public Switched Telephone Network. Technical term to describe the fixed, wired phone system – as operated by British Telecom.

Remote interrogation
Answering machine facility that allows messages to be retrieved from another phone.

REN
Ringer Equivalence Number. Printed on all BT-approved fixed phones and peripherals. The sum of the RENsof all devices connected to a normal wired phone line should not exceed four.

Repertory Dialling
Sometimes known as "memory dialing" or "speed-calling." A feature that allows you to recall from 1-to-99 (or more) phone numbers from a phone's memory with the touch of just one, two or three buttons.

Roaming
Using your cellphone on networks other than the one to which you pay your monthly line rental. In other words, using your phone abroad. Roaming is available on all of the UK digital networks. How many countries you can roam to will depend on the number of roaming agreements your network has signed, and on the type of phone you have access to. Roaming must be requested from your network or airtime provider.

RF
Radio frequency. Term used to describe the signal transmitted or received by a mobile phone.

RS232
Connection socket commonly found on computers. Some cellphones have the ability to be connected to a PC through this socket to facilitate the updating of personal directories, or for writing SMS text messages.

Scanner
Radio that is capable of scanning hundreds of frequencies. Used by enthusiasts to monitor PMR, emergency service, analogue cellular, and air traffic control transmissions. The essential device for the criminal who wants to clone analogue cellphones.

Scratchpad
Common feature on cellphones that allows you to store a number in a temporary memory on the handset while you are having a conversation.

Service Plan
A rate plan selected by subscribers when they start up cellular service, usually consisting of a base rate for system access and a per-minute rate for usage. Service plans are designed to provide the most cost-effective rates for different types and amounts of usage by the cellular subscriber.

SIM
Subscriber Identity Module. The smart card used in digital phones. It carries the user’s identity for accessing the network and receiving calls and also stores personal information, such as a phone directory and received SMS messages. Mini-SIMs are the size of a postage stamp.

SMS
Short Message Service. Two-way text messaging service is offered on all four digital networks. Messages of up to 160 characters can be sent at low cost. Some older handsets only allow incoming messages (mobile-terminated SMS – or SMS-MT); all new phones also allow you to write and send text from your handset (mobile-originated SMS, or SMS-MO). Can be sent between phones on any network.

Softkey
Button on a mobile which changes function depending on what you are doing with the phone. Its current function highlighted using a keyword immediately above the button on the phone’s LCD screen, helps greatly in simplifying the use of cellphones.

SOHO
Small office – Home office. Category of products or services designed to appeal to those working from home. These people are also known as teleworkers.

Standby time
The number of hours that a freshly-charged battery will keep a mobile running without making or receiving a call. When it is switched on, power is used continuously by the phone to keep it in contact with the local cell site, so that the network knows where you are, should you receive a call.

TACS
Total Access Communications System. Original analogue standard used in the UK. See ETACS.

Talktime
The number of minutes of continuous speech that a freshly charged battery will allow you to make on a cellphone.

TDMA
Time Division Multiple Access. Type of processing system used by digital mobile phones that allows several handsets in the same area to use the same frequency. Each conversation is allocated its own time slot – so that you only hear the conversation for the fraction of each second. However, as the interval between each burst of signal is small, these gaps are imperceptible to the two people having the conversation. Both GSM and DECT use TDMA to ensure efficient use of allotted frequencies.

Transportable
The transportable cellular phone is a standard mobile phone that can be removed from the vehicle and used by itself with an attached battery pack. The entire unit is generally mounted or built into a custom carrying case to make it easy to carry. Although technically "portable," the transportable should not be confused with smaller, one-piece cellular phones.

Travel charger
Small charger that connects direct to a socket in the phone. Unlike with a desktop charger, there is no cradle to support the handset.

Tri-band
Triple-band phones are capable of operating on three GSM frequency bands – the GSM 900 and GSM 1800 frequencies used in over 100 countries worldwide plus the GSM 1900 frequency band that’s increasingly being adopted in America.

Trickle charger
A charger which takes eight or more hours to replenish the battery. Better for longevity of battery, but less convenient than fast chargers.

T9
Predictive text inputting system designed (by Tegic) to make text message writing easier. Instead of having to select letters individually by pressing each key numerous times, mobiles with T9 software ‘guess’ what you’re writing as you go along, reducing the number of key presses required.

UMTS
Universal Mobile Telecommunications System. New mobile communications standard offering numerous voice, data and multimedia applications. The eventual successor to GSM, the first UMTS network will begin to be deployed in 2001. See IMT-2000.

Voice Activated Dialling
A feature available only on selected phones that permits you to dial numbers by calling them out to your cellular phone, instead of dialing them manually. This function is especially convenient for making calls from your vehicle while driving.

Voice recognition
Facility offered by a few handsets enabling calls to be made by using voice commands rather than punching in numbers. The memory can be programmed to store and identify names spoken into the handset and call numbers associated with them.

Voicemail
Mobile phone service provided by the networks that records a message for you when you can’t, or don’t want to answer a call. Unlike a traditional answerphone, the system can take messages for you when you are using the telephone.

WAP
Wireless Application Protocol. An agreed standard which enables WAP-compatible mobile phones to access Internet-type services (such as news, travel, entertainment, finance, sport etc) via their menu system and LCD screens.

WCDMA
Wideband Code Division Multiple Access. Air interface standard which will enable Third Generation mobile phones (due in around 2003) to carry new mobile multimedia services (see UMTS).