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A pager is a small telecommunications device that receives (and, in some cases, transmits) alert signals and/or short messages. This type of device is convenient for people expecting telephone calls, but who are not near a telephone set to make or return calls immediately.
A typical one-way pager fits easily in a shirt pocket; some are as small as a wristwatch. A miniature, short-range wireless receiver captures a message, usually accompanied by a beep. (This is why the device is also known as a beeper). The simplest one-way pagers display the return-call telephone number of the person who sent the message. Alternatively, a code can be displayed that indicates which of several designated parties is requesting a return phone call. Sophisticated one-way pagers can display short text messages.
Until recently, pagers were designed as receive-only devices. There are at least two reasons for this. First, if two-way communication is needed, cell phones are available for that purpose. Second, it is difficult to engineer an efficient wireless transmitter that can fit inside a tiny package and provide enough signal range to reach repeaters from all points within the coverage zone.
Despite the engineering challenge, a two-way pager, also called a two-way messaging device or two-way interactive system, has been developed. This system employs large numbers of repeaters, allowing low-power wireless transmitters with subminiature antennas to reach at least one repeater from any location within the coverage area. A typical unit is about the size of a pocket calculator and has a built-in, miniature keyboard and a liquid crystal display (LCD) screen that can display several lines of text and/or simple graphics.
Last updated on: Jul 17, 2007
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