Or cellphone; Mobile radio telephone, one of a network connected to the telephone system by a computer-controlled communication system. Service areas are divided into small “cells”, about 5 km/3 mi across, each with a separate low-power transmitter.
The cellular system allows the use of the same set of frequencies with the minimum risk of interference. Nevertheless, in crowded city areas, cells can become overloaded. This has led to a move away from analog transmissions to digital methods that allow more calls to be made within a limited frequency range.