I’ve been pondering this for quite some time and, since I’m trying to do as little hand waving as possible in my science fiction story, it is really bothering me. How exactly does someone actually connect to another person over interstellar distances when they don’t know where they are? Or even if they do?
Nobody has a ‘phone number’ that we know of, yet somehow I can be on some space station and want to send a message to a ship out in the dark reaches and it just happens. Now short-range comms make sense, two ships within range of one another can easily talk directly. To use an analogy, short range comms are like 2-way radios. One walkie-talkie broadcasts a signal that is picked up by the other radio and voila you’ve sent a message and they’ve received it. It makes sense and with our current technology today we can do this with targeted transmissions to minimize on eavesdropping, or use encoding.
But interstellar distances, particularly real-time transmission (implying superluminal) would have to be different. A station in orbit around one star, wouldn’t just send a broadcast out and hope that their recipient can pick it up and have their antenna in the correct orientation. The signal would have to be incredibly powerful at it’s source because the signal would lose strength at an exponential rate as it spread further and further from the source. That would be a tremendous waste of energy wouldn’t it? At least from our perspective and understanding today.
The two mainstream giants (Star Wars and Star Trek) both have a similar explanation of the medium they use. They are remarkably similar too. A network of communication relays that work like internet routers do: taking message streams from nearby vessels/stations and routing them along the network to their destination. However, the problem is greater than just the medium. The real problem is the routing. Internet servers don’t move around (typically). So it is easy to route traffic to them.
But space travelers are always gallivanting around the galaxy, so the closest thing we have to that is our mobile phone networks. But there is the catch. We pay the people who run those networks to use them. Starfleet gets a pass because they are supposed to be a benevolent organization and have given up the concept of monetary compensation for work. Star Wars gets a pass because the holonet was created by and maintained by the central galactic government: the old/new republic or empire. So that covers them.
You also get a free pass if your interstellar network was constructed by “the ancients” and everyone uses it without actually needing care, maintenance, upgrades, or expansion.
But what about everyone else? What about the galaxy that is ruled by a hodgepodge of mega-corps, local governments, and independents? Randolph Lalonde gave hints of this in his Spinward Fringe series when he described having to pay subscriptions to space stations to use their navigation network for docking. But some podunk independent world isn’t going to have the resources to distribute their own network of relays across the stars. Also, the resulting isolation doesn’t exactly make for an exciting adventure. So there must be some kind of communications provider, or multiple.
However, with the slightly dystopian premise of those types of stories, I highly doubt it would be free for everyone to use. Which leads me to: “Who pays for it?” Individual beings? Local governments? What about merchant ships?
Since we are already moving in this direction, the answer must be that everything is data; be it voice, video, or otherwise; and there is an interstellar internet of sorts. (Is net-neutrality an issue in your universe?) Still there is problems, we all have a difficult enough time creating a username on a forum or website that isn’t already taken, so how does a message even get addressed properly to a recipient, when we’re talking about billions of star systems each with billions of inhabitants? Do you have to know the unique transponder code of the vessel or station they’re on? What if you don’t?
There are many questions that get brought up about what is actually available to travelers in the black. Even the US Navy has a problem with sailors getting stressed while at sea because the only have limited access to the internet. Maybe you are truly isolated out there. Seems also very conceivable that there could be coverage problems with the interstellar network. Maybe you’re out in a sparsely populated area and there are no local beacons to connect to. Maybe some kind of baddie has blown up the local transponder. There’s some very realistic plot points for you. Maybe you’re a fugitive and you’re account was flagged for tracking when your warrant was issued. Can you even get a ‘burner’ comm? Maybe you got fired from your job and the company was covering your network expenses, what happens then?
Maybe there is really a secret communications utopia in science fiction where the infrastructure is magic and everything is free to use and most especially nobody asks too many questions about it.