Radio paging systems

(communications) A system consisting of personal paging receivers, radio transmitters, and an encoding device, designed to alert an individual, or group of individuals, and deliver a short message.

Systems, consisting of three basic elements—a personal paging receiver, radio transmitter, and an encoding device—whose primary purpose is to alert an individual, or group of individuals, and deliver a short message of a temporary or perishable nature. Characteristics that are used to define a specific paging system include distance covered, radio frequency, modulation type, paging code format, and message type.

On-site systems cover a single building or a small complex of buildings typically utilizing one low-power transmitter. Wide-area systems can cover an entire city or country and usually use multiple transmitters which simulcast the paging signals. Most paging systems now utilize the very high-frequency (VHF) or ultrahigh-frequency (UHF) radio spectrum using frequency modulation (FM). See also Frequency modulation; Radio spectrum allocations.

Paging receivers fall into four basic categories: tone alert, tone and voice, numeric, and alphanumeric. Tone pagers emit a “beep” when they are signaled. Some models silently alert the user with a vibration in place of a beep; other models use differing staccato beeps to provide the user with several alert messages. Tone and voice pagers allow the initiator of the page to transmit a simple voice message which will follow a pager's beep alert. Numeric pagers, sometimes called digital pagers, allow the initiator to convey numerical information. These messages are typically composed by using a tone telephone key pad. Alphanumeric pagers allow the initiator to send a complete textual message to the pager user. These messages are composed on word processors, personal computers, or dedicated terminals which can connect to a paging terminal. See also Microcomputer; Word processing.