Eli5 how did pagers work?
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If we’re going to keep it at an ELI5 level, it’s basically a cell phone, that only receives text messages.
Most people were not texting, you would call the pager from your phone. You would then hear a beep, and type in the number you want to send, or maybe your family had a code setup. -911 followed by your phone number would mean call home right this second.
There are of course, some differences, pagers use VHF radio signals, which travel much further than cell phone signals. This is why some are still in use today. Its simple technology that works, and has great range. (So a hospital or Mountain rescue team might use them where a cell phone signal would be unreliable.
Another major difference between pagers and SMS, is pager networks just send the signal out once, then forget about the message. Maybe its received, maybe it isn’t. The network doesn’t care, and there is no way on a lot of pagers to acknowledge the message was received. (Some pagers did have this feature to acknowledge a message)
With SMS, if you our out of range, or your phone is off, the network will store the message until you get back online.
one thing is how long the battery lasts
turning the radio on to listen costs energy. (battery life)
there is something called the paging cycle, basically when the barrety is removed and reinserted (reset) the pager enters hunting/synchronization-mode.
to simplify think about 10 second cycle. at second 0 the tower broadcasts a “drum beat” precisely timed. the pager uses this to start a timer, each page has a time slot number (ie: 1 to 10) the pager now goes to sleep until right before its time slot then turns the radio reciever on, waits for its cycle to complete and then goes back to sleep.
when sleeping it draws as much as a wrist watch (almost nothing), it daws alot (relatively) when the radio is on.
if the tower tansmits that pagers id number during that time slot the pager buzzes or displays the message sent.
this link (highly technical) talks about the paging cycle in lte phones, youll notice they use the acronym UE this stands for user equipment
your cell phone uses this to wake up and ring..
if you ever notice your phone sesrching for a service it is listening for a tower.
this is why when you fly or go places with no signal your phone battery dies fast it keeps hunting and that requires the radio to be on 100% of the time
that timing accuracy is one of the reasons your phone has GPS it gives your phone a super accurate time base to synchronize with the tower time better
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