Mobile phone

A cellphone or cellular phone, also known as a mobile phone, is a portable electronic device which behaves as a normal

Technology

Though cellphones vary significantly from provider to provider, and even nation to nation (most noticeably in North America), all cellphones must generally accomplish the same tasks regardless. Cellphones must be connected to the system of land-line phones. Cellphones must also be able to connect with each other just as easily, even if the two phones are not from the same mobile service provider. Consequently, all cellphone systems are comprised of two components; the handset, and the tower. The handset is the portable, refered to as the mobile phone, cellphone or a smartphone. The tower is a high-yield radio tower that the cellphones direct their radio communications to in order to connect to the network of telecommunications. It could also be a network of satellites.

Related Topics:
North America - Land-line - Satellite

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Handsets feature a low power transceiver that is typically designed to transmit voice and data, or analog audio only, up to a few kilometers under ideal situations to where the tower is located. The handset listens for an available tower. Once found, the handset informs that tower of its own unique identifier, and alerts the cellphone network that it is ready and standing-by to receive telephone calls. It then periodically repeats this information to the tower, and seeks out new towers over the duration it is powered on.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Towers are large structures that feature a series of high power radio transmitters designed to broadcast their presence and availability, and relay communications to the mobile handsets. The tower features a much higher-powered radio transceiver array that allows it to provide a radio communications dialog with handsets dozens of kilometers away. The tower is connected to the landline telephone infrastructure by a high-capacity phone line, and may also be connected to a dedicated data line. The tower can then route calls between the mobile handsets it's serving, and telephone calls over the landline. Because the tower tracks and relays what mobile handsets it is servicing, it can inform the mobile network provider so that at any given time a call to a cellphone can quickly be traced to the tower that is servicing that handset.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Most cellphones dialog between the handset and the tower is comprised of a data stream of digitized audio. The technology driving this process can vary, and in nations with no standard or preference (such as the United States), many incompatible technologies exist. Not only do transmission standards potentially differ, but so do the radio frequencies. Some technologies include AMPS for analog, and TDMA, CDMA and GSM for digital communications. Though nations like the USA have generally avoided official standardization, most nations of the world have agreed upon the GSM data transmission protocol for cellphones, and a small range of possible frequencies that cellphones may operate on. Phones are classified based on the technology they use and the features they have. See the table on the right for a comprehensive listing.

Related Topics:
United States - AMPS - TDMA - CDMA - GSM

~ ~ ~ ~ ~ ~ ~ ~ ~ ~