The history of the pager goes back to the 1930s, when the Detroit Police Department developed a radio paging unit specifically used for police departments, military officials and government agencies. Despite the obvious opportunity for profit and consumer use, it wasn't until 1977 that Motorola came up with the Pageboy, a unit that had no display, but had an audio tone that beeped when notified. In the 1980s, digital pagers were introduced, which led to the advanced technology we see today.

Pagers work by combining telephone and radio technology. When a caller dials the specific number designated to an individual unit, a paging terminal receives the message and then sends it to a paging transmitter via wire or radio signals. From the transmitter, the message is sent by radio waves over a frequency used by the paging service. The message is successfully delivered as long as the pager is within range of the transmitter's coverage area. The pager receives the message and notifies the pager's owner through a beeping sound or a vibration. 

The following is a guide to help you understand the varieties of pagers, their inner workings, the components that make them up, and the accessories that you may or may not need.

The different types of pagers vary from a simple beeper unit to entire communication systems that can show updated stock quotes.

• Tone-Only. Better known as "beepers," these pagers announce that a person has called, but do not tell you w

  "You called me here for this? The Batsignal is not a beeper." - Batman (Val Kilmer) in Batman Forever

  here the call is coming from. Usually this type of pager is used for a workplace, where the page is coming from an operator who would be called by the recipient when a page is received. The recipient would then call a designated number to check their messages.
  
  

• Tone/Voice. This is a beeper with access to voice mail. The caller leaves a message, which then sends a tone to the recipient. Like the tone-only pager, this service is operator-assisted - the user must call an operator or service.
  
  
• Numeric. Contains a 20-digit LCD screen that displays incoming phone numbers. Text messages do not appear on the screen, however.
  
  
• Text Messages. These pagers use a wider screen than numeric pagers, and are capable of holding 80 characters. This means you can receive the entire message on the pager without having to call an operator. Text-message pagers also have the ability to store messages in memory, with some able to hold up to 20 messages.
  
  
• Two-Way Paging. These pagers allow direct text messaging between two parties. 
  
  
• Ideographic Paging. Helpful for international needs, these are capable of displaying ideographic languages, such as Chinese and Thai.

The official high-tech philosophy seems to be "more stuff is good." Therefore, the better the pager that you purchase, the more of these features will be included:

Information Service Capability. This feature, which is found on many text pagers, allows the user 

to access information such as news, sports, weather and stock information.

Display Lines. These are the number of lines that appear on your display screen. Most numeric pagers are limited to only one line, but some of the text message pagers can show up to nine lines.

Backlit Display. A light that allows the user to read messages in dark situations. Ideal for movie theaters and while driving at night.

Battery Power Notification. Informs the user when the battery on their pager is running low.

Vibrating Alert. An alternative to the audio signal alert, this feature notifies the owner with a silent vibration when a page comes in. This is a great feature to have when at a public place where silence is needed.

Phone/Address Book. Allows the user to store phone numbers for later use. On text pagers, names and addresses can also be kept.

Message Preview. Text pagers have this feature, which allows a viewer to read the first line of a message in their storage to see if it is one that the viewer wants to read.

Timestamping. Notifies the user as to the time and date a message was transmitted.

Battery Backup. Allows a pager's memory to remain while batteries are being replaced.

Reminder Alert. Notifies the user if there are messages on the pager that have not yet been reviewed.

Alert Options. Allows the user to choose the way that their incoming page will be heard. Options for most pagers include vibrating alert, melodies, jingles, beeping, or a light indicator.

FLEX Capability. Created by Motorola but found in most pagers, FLEX increases the reliability of a pager while 

reducing the draining of power placed on the battery.

Message Memory Capacity. The total number of messages that a pager is able to hold in their memory.

The following are little extras that can be purchased to improve your paging experience:

• Pager Clip. Connects the pager to a pocket or belt, allowing the user easy access and freedom of movement. Valuable for people on the go.
   
• Pager Case. Coverings that can be placed over a pager to protect it from damage. Pager cases are usually plastic, lightweight, and include a clip.
  
• Pager Chain. Links a pager to another object, such as a key chain or belt loop.
  
• Battery Charger. Recharges the battery when it's low. Hook the charger to an outlet and place the pager in it for the recommended period of time, and your pager will be fully rejuvenated.