In recent events, I learned that some pagers only have receivers. How are discrete messages sent to these devices? How is it authenticated? How do they know the device got the message?
Back in the ancient times when I got one we had to page the weed guy to get weed. We out our phone number + 420 (truly a mastermind of code no one would ever break) then he would page back with a time (ex 20) to roll through the burger king drive thru where he was the assistant manager. Then just ordered a whopper with extra lettuce (another brilliant code guaranteed not to get broken) then we just paid $10 more than the damn sandwich we didn’t want but would soon be fighting over.
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At my old house I picked up pager traffic on a software defined radio and decoded it. Everything I’ve ever seen has been unencrypted.
Basically the pulses come from the towers the first X number of pulses are the address kind of like the phone number for the pager. All pagers listen to all pulses and just ignore the ones that aren’t addressed to them.
Here’s some details on one of the more popular protocols
They’re sent like a phone call. Afaik there is no confirmation on the network whether the device received the message.
So they just broadcast the messages from all the towers in the network? In plain text I hope.
My understand is, yes. They just broadcast the message on all towers in an area. The pager may be a simple one-way passive device. Or, it might have just enough broadcast ability to periodically ping a cell tower.
Pagers still have some specialized use cases. One of these is hospitals. A lot of hospitals still use them. Hospitals, as structures, are designed to the most strictest structural codes of any kind of building. If an earthquake or hurricane happens, you want your hospital to be the LAST building that ever falls over. So hospitals tend to be big, heavy structures that are massively over reinforced, way beyond what commercial or residential buildings would be. If you look at hospitals, they just look different as buildings. They’re hulking leviathans of structures.
While this makes them damn-near indestructible, it also can make it really difficult to get cell signals inside of them. Cell companies don’t like wasting power broadcasting signals strong enough to penetrate bunkers. They size their towers so their signals can penetrate most common buildings.
But “penetrate” is a complex term. If you only need to transmit a simple message, a lower-quality signal is often fine. Think of the difference between talking and shouting. In a noisy environment with lots of interference, we automatically switch to a form of verbal communication, shouting, that can overcome a lot of noise, but has a low information density. You can shout to be heard over a din, but you’re not going to be able to communicate subtle emotional context by minute tones in your voice.
Alternately, you can think of it that a simple message can easily be repeated many times. Want to make sure a simple text message gets through? Broadcast that thing 10,000 times in a row. That 10,000 times will still represent a fraction of a second of the data volume needed for a video call. But the pager can piece together the message from the few hundred fragments of messages that manage to get through.
I’m sure the actual network protocols are complicated, but I’m just talking about general communication here. The key is that for many reasons, you can often trade communications reliability for communications complexity. A video call will only work in perfect conditions. A simple page will penetrate thick concrete walls and work in the worst of weather events.
Oh, and often hospitals will actually install their own pager repeaters or independent pager systems right on site. In that case, the network doesn’t need to worry at all about figuring out what tower to send the signal to.
Pagers operate at a lower broadcast frequency than cell phones. Longer wavelengths (low frequency) are less impeded by walls and interference.
I have no idea how this relates to wood, but I very much enjoyed your comment!
Yeah it’s not as secure but it has privacy advantages since there’s no 2-way communication.
But… 2-way pagers also exist. I’ve known nurses that had them for work.
Yeah and my guess is that they’d be less private because if they act as a transmitter, I think they could potentially be triangulated.
In the past, definitely. I’m not sure what the current system is.
Realistically, might as well read https://en.wikipedia.org/wiki/Pager as it knows a lot more than I do. I had a pager for several years and have done network programming, that’s about it… i have an insulin pump that people often mistake for a pager though, ha. It makes me look pretty cool.
They are receive only devices that work using radio signal. Messages are sent using a transmitter of some type. I understand this is a very basic description, I’m not an expert, just have an interest in telecommunications related things.
