In a future where there is no Internet allowed, how might people communicate via texting?

Question

Let's imagine a closed-system (let's say "City under a dome" controlled by benevolent corporate overlords) where there's no Internet because it's not allowed. The infrastructure exists, there are satellites out there, but they're tightly controlled so that no Internet is able to form inside said dome. Now let's allow for there to be a population that lives outside the dome with limited access to resources. They can't control the satellites or make use of existing infrastructure (except perhaps by bootlegging or hacking their way in). What infrastructure would be necessary for them to have rudimentary devices like cell phones that allow strictly for texting between members of the same network?

EDIT: To be clear, I understand that satellites are not used in cellphone communications and that the Internet is unrelated to communications of this kind; I just needed to specifically rule it out as an option in coming up with some way to communicate between devices. So if repurposing existing towers that may have once be used for cell phone communications is sufficient, that's helpful to know; in what I'm writing, the people who live in this area outside the "dome" (it's not a dome, just using this verbiage for illustrative purposes) use messenger devices like pagers to text to each other, so I just wanted some speculation on what technology they might be using. My question is not ridiculous, so please be civil in your speculations. For example, a couple suggestions were ham radios or pagers, using bluetooth, or optics/lasers. These are the kind of answers I was looking for.

Answer 1

A cellphone network can be used for SMS (Short Message Service). No internet as it is understood today is required for it, and neither are satellites. All it takes is a network of antenna mast to route selective calling between handsets.

Historically, mobile phones and non-mobile internet began to get off the ground separately, only later the bandwidth became available to bring mobile phones into the internet as we know it.

Answer 2

You may be confusing internet with websites and apps.

The internet is a network of computers, working on information through layers of protocols.

If your citizens have electronics and radio communication, the only thing keeping them from building their own network is lack of knowledge. Sooner or later someone will build a modem - a machine that translates analogical signals into digital ones, and vice-versa - and then it's just a matter of time until people have a proto-BBS.

You want people to have no network, you keep them from electronics - or you make sure to kill any kid that shows even a slight sign of being an engineering nerd.

Answer 3

For starters, it's important to note that neither the Internet nor cell phones rely on satellite infrastructure. Cell phones use a radio-frequency connection to local towers that form "cells" of connectivity across an area. The Internet is defined more in terms of communications protocols; how the messages physically get from point A to point B is immaterial, and will usually consist of a mixture of local RF, wired connections, and satellites.

Your outside population has a couple of options in terms of how they communicate. One is to essentially (re)build a standard modern cell network. In essence all this is is a set of radio towers distributed over the area they're operating in. Phones communicate with the towers, and towers communicate with one another to send messages where they need to go. The big limitation is that building towers is a little expensive and quite visible, which might be bad if the government disapproves of what they're doing. Range is highly dependent on terrain but in practice is probably tens of miles at best.

The second option is to have devices communicate directly to one another - basically walkie-talkies, but with text rather than voice. This eliminates the need for centralized towers, but at the cost of range: for a handheld unit, I'd say generally no more than a mile.

A third option is landlines. Smaller, more discreet local transmitters could be connected by wired connections very safely over long distances. The lines will need to be maintained, though, and if discovered by the government they might be tapped or just cut.

If you have more time and clever people than resources, you could optimize your network by bridging all of these technologies; this is mostly down to the software you're using, rather than hardware. Your phones could have the option of connecting peer-to-peer within range rather than via a tower, or connecting via a third unit as a bridge, or even over landlines. Techniques exist for efficiently routing messages across complex, heterogeneous networks; indeed this is basically how the modern Internet works, so a lot of effort has gone into laying the groundwork you'd need to use, just at a smaller scale.

Answer 4

Amateur radio.

Ham radio has been around for 100 years, and was originally used to send Morse code. Ham radio operators can send messages for hundreds of miles using privately owned radio equipment. Amateur radio has long been a refuge for persons conducting unsanctioned communication or communicating without the use of established communication infrastructure - because it was not built or it has been destroyed in a disaster.

People do send texts via ham radio - apparently in many different ways!

http://www.aprs.org/aprs-messaging.html

Answer 5

You could have devices that rely on optics to transmit the message, such as the remote controls or combining laser pointers of different colors, an adapted modems .