A pager is a very simple radio that listens to just one station all of the time. A radio transmitter broadcasts signals over a specific frequency. All of the pagers for that particular network have a built-in receiver that is tuned to the same frequency broadcast from the transmitter. The pagers listen to the signal from the transmitter constantly as long as the pager is turned on.
Each pager has a specific identification sequence called a Channel Access Protocol (CAP) code. The pager listens for its unique CAP code. When it hears the code, it alerts the user and may provide additional information, depending on the pager type.
There are five basic pager types:
- Beeper - The first and simplest form of paging, beepers provide a basic alert to the user. They're called beepers because the original version made a beeping noise, but current pagers in this category vary in the type of alert. Some use audio signals, others light up and some vibrate. Many of them provide a combination of alerts. This is the category that the majority of restaurant pagers fall into.
- Voice/Tone - These pagers provide the ability to listen to a recorded voice message when you are alerted that you have a page.
- Numeric - These pagers provide the ability to send a numeric message, such as a phone number, along with the page alert.
- Alphanumeric - These pagers provide the ability to send a text message along with the page alert.
- Two-way - These pagers provide the ability to send as well as receive messages.
Regional and national paging networks set up towers, like those used for cell phones, to cover large areas. On-site paging systems like the ones used by restaurants use a small desktop transmitter. In the next section, we will take a closer look at this device.