A long time ago, before today’s cellular telephones, there were mobile radio telephones or car phones. In most cities, there was only one ‘cell’ (transmitter tower) per frequency so that frequencies (called channels) had to be shared by all users. That meant there could not be a whole lot of people on each channel. Cellular systems now reuse channels by using directional antennas and low antenna elevations so more people have access to the spectrum. Plus, digital technology makes it possible to share a channel without causing interference.
Back in the day, by which I mean the early 1960s, access to the mobile telephone system was very limited and the service was), plus a monthly fee for service. The telephone company really liked those people who got the service and rented the radio telephone equipment. Anyone who wanted to use their own personal equipment was put on a long waiting list.
