Pagers

Last updated: December 3, 2009.

Beep beep beep! Beep beep beep! Before the days when cellphones started interrupting our lives, there was another form of instant messaging system called paging. Mobile phones have made pagers less popular than they were in the mid-1990s, but paging (or radio paging, to give it its full name) is still a vitally important form of sending messages—especially for doctors and emergency workers. Let's take a look at how it works.

Photo: A modern Motorola Bravo pager. This one has a two-line alphanumeric display and scrolls messages from right to left or up and down, as you prefer. It can either receive pages silently and discreetly, or it can signal a new message by vibrating or beeping. It runs off a small battery that goes in the slot at the bottom.

What is a pager?

Broadcasting (sending instant information to hundreds, thousands, or millions of people at a time) is the big idea that made radio and television so powerful. But what if you want to send a message to only one person? You can certainly send very personal messages over the radio: think how people get their favorite DJs to read "happy birthday" messages out on air. That's instant communication and it works fine if the recipient of the message happens to be listening—but it's a bit hit and miss. And it can be irritating for the other two million listeners who have to "tune out" this irrelevant information that has nothing to do with them!

A pager is a small personal radio receiver that you carry around in your pocket. You have a personal code number or phone number and anyone who wants to send a message to you dials or quotes that number with the message they want to send. That puts them through to a switchboard at a central message broadcasting office, where a person (or more likely a machine) immediately sends out the message with thousands of others, just like a normal radio broadcast, using a network of radio transmitting antennas. All the pagers in people's pockets are constantly picking up all the messages being sent out, but your personal pager ignores any messages that don't contain your personal code. Once a message comes through with your code, your pager buzzes or beeps and displays the message with the date and time.

Types of paging

There are two different kinds of paging: limited range and wide-area. As the name suggests, limited-range paging sends messages over a relatively small area using a low-powered transmitter. It's perfect for sending emergency messages to all the doctors in a hospital, for example. Wide-area paging is more like national radio broadcasting. A system of radio transmitters sends pager messages across a whole country in hopes that you'll be somewhere near one of them. In the UK, for example, the wide-area paging network uses something like 500 transmitter antennas—more than enough to cover a country that size.

Pros and cons of using a pager

You might think the big disadvantage of paging is obvious: it's a one-way form of communication. If you receive a pager message, you probably have to find a telephone to call back and find out what's going on. But pagers are not really meant to be competing with cellphones: they have a very different purpose—receiving quick, instant messages—and for this they're often much more efficient than phones. Incidentally, two-way pagers (which allow users to indicate that they've received messages) have been widely available since 1995.

What's so good about pagers? One big advantage is that they send messages with VHF (very high frequency) radio signals, broadcast at about 150 megahertz (similar to normal FM radio programs). Using high-frequency radio means the signals reach further, need fewer transmitters, and suffer less from interfering obstacles than cellphone signals. You're much more likely to receive a pager message in a remote area than a cellphone call or text message, where you may not even pick up a signal. (That's why pagers are often used by mountain rescue teams and lifeboat crews.) Unlike cellphone SMS text messages, wide-area pager messages are typically broadcast and received within 30 seconds. Messages sent over local paging networks, such as those operated by hospitals for their doctors, can be sent and received within five seconds. (Compare that with SMS text messages that can take minutes, hours, or even days to get through if there's congestion on the networks.) It's true that pagers are generally designed for one-way communication, but the lack of a radio transmitter makes them very suitable for environments such as hospitals where mobile phones may be dangerous to use (because their transmitters could interfere with medical equipment).

A brief history of pagers

• 1921: A primitive form of paging is pioneered by the Detroit Police Department, who use radio transmitters to send alerts to squad cars.
• 1949: Canadian inventor Al Gross (1918–2000) invents the first telephone pager. He had already invented the walkie-talkie (in 1938) and Citizen's Band (CB) radio (in 1948).
• 1956: The Motorola electronics company invents the first portable paging device: the Handie-Talkie radio pager. It is soon taken up in hospitals and factories.
• 1974: Motorola introduces the Pageboy I, the first commercially successful pager. It's followed by the even more successful Pageboy II.
  
• 1986: Motorola develops the Bravo numeric pager. It soon becomes the world's best-selling paging device.
• 1995: Motorola introduces the first two-way pager (the Tango).