Pager

I

Introduction

Pager, portable, lightweight electronic device that can receive and usually send coded radio signals that display as a short text message or that indicate that someone is trying to get in touch. Sometimes called beepers, pagers are mainly used by emergency services personnel and by hospital and healthcare personnel. They are also sometimes used by people in restaurants, factories, and other commercial businesses or work situations. Cell phones, personal digital assistants, and text-messaging devices have largely replaced pagers for ordinary personal communications. Pagers operate on different radio frequencies from cell phones and so may work in situations where cell phone service is unavailable (see Wireless Communications).

Signals alert the pager’s user by triggering a tone or a vibration. Most pagers can also deliver brief messages on liquid crystal displays. Because pagers do not rely on telephone wires, a page can be transmitted from a central location and received anywhere within the range of the transmitting tower. Small-scale radio-transmitting devices can provide coverage for paging in places where cell phone coverage may be limited, such as hospitals, factories, or restaurants. More powerful radio transmitters that reach wide areas are used for fire, police, and safety workers, often run with personal-computer-based paging systems that allow messages to reach thousands of people at a time.

Pagers monitor specific radio frequencies used by the service providers. The transmission of the page is encoded so that only the intended recipient of the page can receive and decode the message. If the pager is switched on and is within range of the radio transmitter, the pager will recognize the coded signal. The pager then converts the signal to data, alerting the owner that a page has been sent with a beep, tone, or vibration.

II

History of Pagers

The use of radio signals to perform one-way notifications began in the 1920s and 1930s. During the same period, mobile radio systems were being developed for police dispatch and public safety services. These early systems broadcast messages to all receivers on the band, and they could not be used to contact a specific party.

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Paging later developed from a one-to-many dispatch service into a system for reaching a single address that corresponded to one pager. Pagers in the 1960s and 1970s were simple devices that used a tone or vibration to alert the subscriber to call a single predetermined number to get the message.

A page was the coded radio signal sent from a transmitter to the pager. Pages usually began with the dialing of a telephone number to the user’s paging service provider, a company that maintained the paging transmitters and radio equipment. Placing a telephone call to the service provider enabled the caller to access a computerized terminal. The caller heard a tone or received instructions on how to page a subscriber. If the caller wanted to leave a telephone number for the paged party to call, the caller could enter that number. Pressing the telephone’s pound (#) or star (*) key informed the paging terminal that the message was complete. Most pagers had liquid-crystal displays that showed the number of the calling party, or short messages. The owner of the pager could telephone the paging party, or call the paging company to retrieve other messages.

The paging terminal automatically determined which pager corresponded to the telephone number dialed. It then routed a signal to one or more radio transmitters located throughout the paging service area. The area could vary; some services were local, while others were networked together via satellite to cover larger regions.

Communications satellites have been used to route pager connections throughout the United States, and in 1998 a satellite failure temporarily silenced millions of pagers across the United States. Pager connections were transferred to another satellite to restore service.

Innovations in computer technology have improved pagers, making them smaller, more affordable, and loaded with new features. Modern pagers have screens that can display numbers or short messages, and they can store those messages for future referral.

See also Telecommunications.

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