A pager is a dedicated RF (radio frequency) device that allows the pager user to receive messages broadcast on a specific frequency over a special network of radio base stations.
 
The first pager-like system was used in 1921 by the Detroit Police Department. In 1949, the very first telephone pager device was patented by Al Gross and used by the Jewish Hospital in New York starting in 1950. These were not consumer units. Al Gross' device did not win FCC approval until 1958.
 
The term "pager" was first used in 1959, referring to a Motorola radio communications product: a small receiver that delivered a radio message individually to those carrying the device. The first consumer pager (as we are familiar with them today) was Motorola's Pageboy I, introduced in 1974. It had no display and could not store messages, but it was portable and notified the wearer that a message had been sent. 
 
By 1980, there were 3.2 million pager users worldwide. Pagers had a limited range, and were used in on-site situations, i.e. medical workers within a hospital. 
 
By 1990, wide-area paging had been invented and over 22 million pagers were in use. By 1994, there were over 61 million pagers in use and pagers became popular for personal use.