(Part 2 of this series can be found here)
(Part 3 of this series can be found here)

When I started doing research for this series of articles, I’d planned on giving a brief, linear history of long-distance communication up to, roughly, the advent of the electronic age. It was supposed to be a sort of chronological guidepost for writing and world-building. After about an hour, the part of my brain that genuinely believed it would be that simple looked up at the other part with overwhelmed puppy-dog eyes, as though it had just been told that its favorite ball was at the other end of a wide river with big shadowy things drifting below the waves. That other part— the one that actually takes five minutes to think and usually handles all the research— looked down at the first and said, without sympathy: “You’re the idiot who thought it’d be ‘linear.’”

The history of long-distance communication is, of course, no more linear than any other form of technology. In fact, for those who want to learn about long-distance communication for writing and worldbuilding, it’s a bad move to think about “chronology” in the first place. What’s important for writers is understanding:

1. What kinds of messages can be sent,
2. Who might send them,
3. And how the needs, resources, and environments of these people affect their development and adoption.

Over the course of the three articles in this series, I hope to give you a solid foundational understanding of all three. To accomplish that, we’ll start by separating long-distance communications into three categories: binaries and pre-arranged signals, simple messages and coded communications, and complex, nuanced messages. Then, we’ll deeply explore each category in an individual article that covers its pros and cons, who has access to it, and how it interacts with different segments of society, using historical and fictional examples to illustrate these ideas. Finally, we’ll close with some thoughts on how to best use these principles in your own worldbuilding.

One last note: while these concepts are applicable to writers of all genres, these theories and examples are mostly focused on pre-electronic communication, and don’t touch on digital communication at all. That said, the basic principles discussed here will carry over even to sci-fi writing, if used right. Now, on to the main show.

From Books to Binaries

“Long-distance communication” is kind of an over-broad term. It’s a little like saying “food.” Yeah, that puppy-dog part of my brain jumps at the word, but it encapsulates a huge spread of ideas that, at their core, share only one element: making that dude over there know something that I want them to know. Problem is, there’s a huge difference between wanting them to know that, say, the British are coming by land rather than sea, and wanting them to understand a nuanced political alliance. The structures and systems necessary to transmit that message (and the reasons you might do so in the first place) change drastically according to the complexity of the message and, to a lesser extent, the environment you’re transmitting it in. Likewise, those structures and systems, themselves, affect who can use them.

So, if your goal is to build solid worlds and understand the theory behind long-distance communication, you have to start by separating messages by their degree of complexity. Broadly speaking, long-distance communication is broken into three categories:

1. Binaries and Pre-Arranged Signals
2. Simple Messages and Coded Communication
3. Complex, Nuanced Messages

Let’s’ give a quick rundown: binaries and pre-arranged signals don’t allow for variety or flexibility, and the kinds of messages that can be sent have to be agreed upon by the sender and receiver beforehand. In other words, that means “yes-or-no,” “one-if-by-land, two-if-by-sea,” and “Flag-at-half-mast-means-Johnny’s-finally-dead.” Simple messages and coded communications are a step up the ladder. These use systems representative of spoken or written language but lacking its depth and nuance—usually as a result of limited space. Morse code is a good example. Complex, nuanced messaging, on the other hand, covers anything you can think of to say or write, and is primarily limited to full-on written communication.

It’s important to remember, however, that a given communication technology isn’t always limited to one kind of message. The environment, needs, and ingenuity of a group or individual can shift a technique from one bracket to the other. Smoke signals, for example, could conceivably be used as a kind of Morse code over a short distance with little wind, or with a kind of wood that made a dense, non-dissipating smoke. And your phone, which can send complex text messages to a friend, can also be used to confirm you’ll be at a party—a binary message. Speaking of…

Quick and Simple: Binary and Pre-Arranged Signals

Binary and pre-arranged signals are deliciously simple. They don’t require any complicated technology (a handful of torches will do), anyone can come up with a system (I imagine you’d be hard pressed to find any culture that didn’t develop simple long-distance messaging somewhere along the line), and their simplicity means that there’s a lot less to get in the way of a successfully transmitted message. This makes binary and pre-coded signals extremely useful for emergency situations where you need to be sure the message makes it through.

Smoke signals are (probably) one of the oldest forms of binary/pre-arranged signaling. Ancient soldiers along the Great Wall of China used smoke signals to warn of impending attacks. One station would light a bonfire, the next would see the smoke and light their own fire, and the next and the next, eventually transmit a warning over 500 miles in a few hours. Likewise, many Native American Tribes had more complex systems of smoke-signaling that could convey a wider variety of messages, each of which would be unique to its tribe or alliance of tribes.  

On the weirder side of things, we have the hydraulic telegraph, originally invented by the Greeks in the 4^th century BC. The hydraulic telegraph used two identical water-filled cylinders set far apart. At the bottom of the container was a spigot, and floating at the top was this little flag-pole-looking thing with different messages scrawled on posts sticking out at different heights. To send a message, one man would light a torch indicating there was a message to send. The receiver would light their own torch and both would open the spigot at the bottom of the container, letting water out. When the correct message reached the rim of the container, the sender would extinguish his torch and the receiver would close his spigot.

Why they couldn’t just light as many torches as there were messages scrawled on the telegraph and put them out to indicate the message sent, I’m not sure. This seems a lot like the ancient equivalent of a McDonald’s picture-based ordering menu to me. Maybe someone needed tenure.

Anyway, binary and pre-arranged messages, due to their simplicity, can be sent quickly, easily, with little training, and you can find something that works in almost any environment. Visual systems are the most common (flags, torches, over-complicated water tubes), but sound is a favorite pick in areas where visibility might be compromised (like heavy fog, mountains, or big cities). In fact, sound can travel farther than visual systems at times, and the acoustics of mountains, big cities, and water could increase that potency. No surprise that they’ve been used for centuries in the form of bells, gongs, drums, and horns.

While an easy example of this is church bells chiming the time over a small town, I’d like to discuss an example from popular fiction. In George R.R. Martin’s A Song of Ice and Fire, the Night’s Watch has a pre-arranged sound-based message system of their own: the horns. One blast means rangers returning, two means Wildling attack, and three means white walkers. It’s a good, if simple bit of worldbuilding. After all, the North’s snowy climate makes sound much more usable than any kind of visual signal. Not to mention one other big benefit…

For Princes and Paupers… but Probably not Poets

Sound can travel for miles and, in good weather, even simple visual systems can reach similar distances. Any further than that and you need a relay system ready to pick up the original message and pass it down to the next person in line. Generally, that kind of communication will only be necessary with large armies or civilizations, which already have the organizational structures needed to set up a simple pre-arranged message relay system. After all, these systems aren’t terribly complex.

That’s one of the greatest benefits of binary and pre-arranged messages, especially for writers. Their simplicity means that nations don’t need to be technologically advanced to set up a powerful long-distance relay system, and small-scale messages can be concocted by anyone. Individuals, families, and even revolutionaries can come up with small-scale systems to fit their needs, including ones that will go unnoticed or uninterpreted by those they don’t want to pick up on them. Big cities, in particular, are great for that kind of subterfuge. I mean, who’s going to notice an unusual chime or flag in the middle of a noisy city, other than someone looking for it?

Likewise, this simplicity means that you don’t need any special training to use a binary or pre-coded system. So long as you have the tools in hand (which, again, could be as little as a torch or a bell) and you’ve been told what symbols mean what, you can communicate. You don’t need to be literate, educated, or even particularly intelligent—you just need to be able to follow instructions. Think back to the horns of the Night’s Watch. Most of the rangers are uneducated, and the horns will only need to be blown in an emergency, which is perfect for such a simple messaging system.

Unfortunately, this simplicity has a downside: by nature, binary and pre-arranged messages can’t send anything complex. And, as they’re limited to a pre-arranged “list,” they’re completely unable to send anything outside of that… which could be a problem if you need to send a distress beacon that also mentions a new, unseen weapon. Likewise, binary and pre-arranged messages are wholly utilitarian. They’re generally not used for “casual” or artistic communication, only to communicate a practical message from one person to the next.

That said, due to their utility and the ease of crafting a binary/pre-arranged signal system, examples of them are positively legion, and many are so deeply woven into our society that we don’t think of them as a form of long-distance communication. It would be impossible to even begin to give a comprehensive list of the breadth of options available, but they all share the qualities we talked about here: they’re fast, easy to make and use, hard to misinterpret, and handy in an emergency, even if their simplicity limits what you can use them for.

Of course, that changes when we get to the kinds of messages discussed in the next article in this series. Hopefully you’ve enjoyed what you’ve read so far and have learned something you can use in your own writing. In part two of this series, you’ll be able to learn about simple messages, coded communication, and how to use a drum to read poetry to people miles away.

And yes, I’m just gonna leave that comment hanging there. Happy writing!

Featured Image Courtesy of Eberhard Grossgasteiger!