One way or two way devices that send messages, or just buzzes, or maybe just beeps, over long distances. Probably so your boss can harass you without wasting sic credit or minutes on your worthless self. Or so your terrorist cell can send you a vague code so that you can assemble at your nearest meeting location.
Oh, but we have radios and phones and neural networks, why would we use a pager?
1. Cheaper than a gridphone.
2. NO VOICE INVOLVED. Anonymity!
3. Probably has better signal than phones do. Definitely has better signal than radios do.
So what are the features of these near-luddic devices?
Three different pager models. One related device.
Cheap as hell. Disposable, even.
Recieves a loud beeping akin to a phone ringing, but infinitely less helpful. Can press the acknowledged button to stop it and send back a simple 'acknowledged' message to the sender. That's it. Beautifully trash.
Cheap, probably around the price of a dirt-cheap gridphone
Recieves a beeping or buzzing, depending if it's silence is toggled. Also capable of recieving an 8 digit number code, and can also send back an acknowledged message to the sender.
These probably cost around the price of a certain mid-grade gridphone.
Recieves OR SENDS a beeping or buzzing with silence toggle, as before. Can recieve OR SEND an 8 digit number code, as well. Acknowledged message obligatory.
And for the final device, a transmitter.
Slightly cumbersome, maybe even stationary, can send number codes or beeps and recieve acknowledgements from pagers. Cannot recieve number codes, only acknowledgements.
How do they work?
Well, each pager should have a serial number akin to a phone number that a transmitter or high-grade pager can send to.