Introduction to telecoms terms and technologies
The telecoms world seems to be crowded with a confusing set of acronyms and technical jargon, which may mean nothing to you and can be difficult to differentiate.
In this information sheet we give a brief overview of some of the technologies and terms you are most likely to come across using TelecomsAdvice. You can find more detailed explanations, as well as information sheets and features covering them in more detail, by following the links at the side of this information sheet.
There are two types of telephone service infrastructure -
- fixed - wired (standard telephones using copper or fibre cables) and wireless (cordless analogue and DECT digital)
- mobile - cellular analogue and digital (GSM), and satellite (Inmarsat and the new low earth orbit (LEO) services)
The technologies used by these services may be analogue, or in the case of newer technologies, digital. Most can be used for more than simple voice telephony, for example to transmit faxes and to transfer files including data, audio and video.
Starting with the most familiar, the technologies currently on offer are listed below.
- POTS - the standard (or "plain old") telephone service, an analogue system using copper wires
- ISDN - Integrated Services Digital Network. ISDN uses the same copper wires as POTS, but by (at its simplest) providing two channels per physical line can be thought of as the equivalent of two lines. In larger installations one physical line can carry up to 30 voice or data channels.
- ADSL - Asymmetrical Digital Subscriber Line. ADSL, which also uses existing copper wires, is a fast and permanent "always on" connection to the Internet, which includes one phone line or voice channel which can be used at the same time
- cable modems - use the hybrid fibre coax (HFC) networks of the cable companies. Shared bandwidth means speeds 5-10 times as fast as single channel ISDN, similar to ADSL. ADSL and cable modem connections are referred to as ‘Broadband’.
- fixed wireless - fixed base station and wireless DECT type handsets are gaining in popularity for voice telephony. Wireless LAN systems using a base station and cards with aerials inserted into computers are on the market and becoming more popular. These wireless LANs are also appearing in shared working spaces although there are some concerns about security of such networks. You may hear them referred to as WiFi or 802.11 networks. An associated technology called ‘Mesh’ turns each wireless appliance into a repeater station so spreading the range of the network.
- GSM - unlike cellular (analogue) mobile phones, GSM is a digital service. It can provide e-mail/text messaging and WAP Internet connectivity, but at a relatively low bandwidth, and therefore slow or restricted functionality
- GPRS - a new data network which offers an "always on" connection to the Internet, and increases the speed at which data is transferred over mobile phones. A GPRS device, such as a desktop/laptop/palm top computer, can be permanently connected to the network through an internal card or external box, with an aerial for Internet and other services. Starting bandwidth is up to 28 or 56kbps depending on strength of signal, with plans to increase this to 128kbps. At the higher bandwidth the service could be a viable, always-on alternative to ISDN.
- third generation (3G) mobile or UMTS (Universal Mobile Telephone Service) will provide fast Internet access, which will in practice enable data transfer and network applications to be used from laptop, notebook and handheld computers
- Satellite phones are bulky and expensive but can be used most anywhere in the world.
There is also a third piece to the telecoms jigsaw - the provider(s) you use to supply you with telecoms services and equipment - see our buyer's guides for further information.
Reviewed January 2011
last updated : 21/01/2011
See also our UK ICT Directory for supplier lists and links
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