Until 1984, mobile telephone service was severely limited. Each city had a single antenna to transmit signals to and from a car phone's antenna. The Federal Communications Commission (FCC) assigned only 12 to 24 frequencies to an urban area, so only one or two dozen car-phone calls could take place in the entire city at one time. Users had to wait up to 30 minutes to get a dial tone, and potential mobile phone customers were put on 5-or 10-year waiting lists.

Cellular telephone (cell phone} technology changed all this. In a cellular system, each metropolitan area is divided into broadcasting zones, or "cells." Each 6- to 10-square mile cell has its own antenna. As a car phone moves through the city, a computer automatically passes its frequency from one cell to the next. A single frequency can be used for multiple nonadjacent cells, and as the number of users...