A pager is an electronic device used to contact people via a paging network. It pre-dates mobile phone technology, but similarly uses radio transmissions to communicate between a control/call centres and the recipient. Many of today's pagers use the FLEX on-air protocol.

Early pagers only provided an audio notification, a bleep or series of bleeps, to indicate that you had been paged. The paged party then had to telephone the control/call centre to collect the message either from an operator or an early voice mail device. Later pagers used text messages to provide the recipient with more information.

Later models included the ability to send messages in a two-way fashion and even included the ability to send email. This is known as two-way paging.

Pagers subscriptions have been on the decline since the widespread availability of mobile phones and their ability to send SMS based text messaging which duplicates the paging function. There has been a gradual consolidation of text messaging, SMS and paging with email traffic and methods. However, this use of the Internet to carry text messaging traffic is subject to unpredictable delays due to router and switch traffic. Older forms of text messaging using TAP protocol involve modem connections directly to a paging network, and are less subject to these delays. For this reason, older forms of paging retain their usefulness for distributing alerts to large numbers of users at the same time; those groups would include emergency services personnel.

Pagers are still in use today in places where mobile phones typically cannot reach users. A good example is deep within a hospital complex where cellular coverage can be problematic. In most situations hospitals will contract out or purchase and maintain the equipment needed to provide this extra RF coverage. It is critical that quality signal reach all of the hospital campus areas so that its emergency staff can respond to patients' needs.

Common paging protocols include: TAP, FLEX, ReFLEX, POCSAG, Golay and NTT. Past paging protocols include: Two-tone and 5/6-tone.

Pager technology is now being used in irrigation control systems and for traffic signals.

Pagers usually have very simple ring tones and some include a vibrating alert.