A pager, also known as a beeper or bleeper, is a wireless telecommunications device that receives and displays alphanumeric or voice messages. Pagers operate as part of a paging system which includes one or more fixed transmitters, as well as a number of pagers carried by mobile users. There are different types of pagers, including one-way pagers that can only receive messages, response pagers that can acknowledge messages, and two-way pagers that can also send messages. Pagers can be used to send numeric messages, text messages, or voice messages.
Pagers were developed in the 1950s and 1960s and became widely used by the 1980s through the late 1990s and early 2000s. However, the widespread availability of cellphones and smartphones with text messaging capability has greatly diminished the pager industry. Pagers are still used today, primarily by medical professionals and emergency responders.
The basic operation of a pager involves a radio transmitter broadcasting signals over a specific frequency, and all of the pagers for that particular network have a built-in receiver that is tuned to the same frequency broadcast from the transmitter. Each pager has a specific identification sequence called a Channel Access Protocol (CAP) code, and the pager listens for its unique CAP code. When it hears the code, it alerts the user and may provide additional information, depending on the pager type.
Pagers have certain advantages and disadvantages compared with cellular phones. Since a one-way pager is a passive receiver only, it cannot be used to track a persons location or to eavesdrop on conversations. However, pagers are limited to receiving messages only and cannot be used for voice calls or internet access.
In summary, a pager is a wireless telecommunications device that receives and displays alphanumeric or voice messages. It operates as part of a paging system and has different types that can receive numeric messages, text messages, or voice messages. Pagers were widely used in the past but have been largely replaced by cellphones and smartphones.