Pager: A Pager is a electronic device with FM radio receiver  which is useful for communication purpose.  Paging service has now popular with the introduction of statelite base stations.

A pager (sometimes called a beeper) is a simple personal telecommunications device for short messages. A one-way numeric pager can only receive a message consisting of a few digits, typically a phone number that the user is then expected to call. Alphanumeric pagers are available, as well as two-way pagers that have the ability to send and receive email , numeric pages, and SMS messages.

Paging was invented by Multitone Electronics in 1956 at St Thomas’ Hospital in London to alert doctors attending emergencies. Over subsequent decades, paging has evolved in technological sophistication.