The History of the Two-Way Pager

An interesting device, released a little too late

In the 90s, pagers were popular: They were cheap, lightweight, and had a very long battery life. But at the same time, they were only able to receive messages. There was no transmitter inside the pager, and there was no physical possibility to send any response. The idea of having two-way communication was tempting, and in 1995 the Motorola Tango, the first pager that was able not only to receive but also to send messages, was made.

Technology

All pagers from the paging provider listen to the same frequency, let’s say, 930 MHz. Every pager has its own unique ID, called CAP — Channel Access Protocol or RIC — Receiver Identification Code. If the message code is equal to the pager code, the pager saves the message and makes the loud “beep.” That’s it. It’s one-way communication. There is no confirmation sent back. The pager has only the receiver and no transmitter at all. The logic and hardware are extremely simple, and because of that, the pager can work for more than a month from a single AAA battery.

This scheme has several advantages. Firstly, all the messages are sent one after another, on the same frequency, which means that the system can’t be overloaded. If the new message is received by the operator, it will be added…