If you find this at all interesting, you have to read Neal Stephenson's classic Wired article about undersea cables - https://www.wired.com/1996/12/ffglass/
The way I'd do it would be to have a big 26-light display, each corresponding to one letter. Then you'd light them up one at a time and have the receiving clerk write down the letters one by one. Efficient? Not very, but I can see how someone without a lot of information theory knowledge (as almost all early inventors would be) would land on that idea first.
There were pre-Morse / Wheatstone telegraph experiments using 26 wires. One notable early system by Salva Campillo used 26+ tubes of electrolyte, one for each letter. Closing the circuit would cause bubbles to form in the tube at the other end.
Even wackier systems from before this time used static electricity ("current" electricity was harder to generate in the early days). One proposal was to have a different servant hold a wire for each letter of the alphabet. At the other end a high-voltage Leyden jar would be connected to wires in turn, giving the servant a shock and prompting them to speak their assigned letter. Unfortunately I can't find the source for this one right now (I think it was in the book The Story of Telecommunications).
This is fibre optics in general. For long distance stuff (>40km) you want to do a search for "coherent optics". A lot of these long distance fibres have multiple signals going down one glass using different colours ("lambdas") which are (de)muxed; see Dense Wave Division Multiplexing:
Always impressed by the amount of engineering which goes into the undersea cables and into fiber optic connections in general. One interesting takeaway (at the risk of mentioning an elon company) is that current-gen satellite connectivity will be massively improved by constellations like Starlink, providing a really nice option to disaster zones and places where normal physical connectivity is interrupted.
We might even see reduction of dependence on undersea cables in general, which seems good considering the passages on fishing, seafloor disruption, and the whole bit about "uhh yeah sometimes these cables are salvaged..."
I am curious about the effects on deep sea marine biology in sensitive areas... most of the ocean floor is desert, but do we have total knowledge about all the places these cables are going through? By fishing activity are we talking about deep sea trawling? The presence of fishing activity implies at least the non-sea-bed areas are in fact not deserted.
I'm surprised how much you seem to worry about ecological impact of deep sea cables... Are there that many? And even if each one were a complete disaster all the way (which seems virtually impossible), it would be... like a one meter strip across the entire ocean that is affected, out of 2500 km?
Could you elaborate what impact you are concerned about?
In the UK, there are these things called ransom strips, a very thin (maybe just a few inches) but long strip of land that is used to control and interfere with other people's access to their own land.
It could be there are some downsides to having a continuous strip/barrier running all the way across the ocean floor. Maybe some sea creature's migration is disturbed/impeded by it - who knows.
I'd be more inclined to think there could indeed be some impact than to just say "no worries, it's only a cable, no big deal on the scale of the oceans".
Humans have an amazing ability to over-imagine the impact of the impressive (running <100 1m-wide cables across the ocean) and under-imagine the impact of the mundane (thousands of cargo ships absolutely making life miserable for whales)
Well darn. Looks like I was wrong, I do appreciate the update and if I am unable to reshape the Earth such that it fits what I said above I will stop spreading the false information :)
From the article, sounds like their currently contracted satellite connections are having trouble due to lingering volcanic ash. Would Starlink fare any better against volcanic ash?
Yes, multiple LEO connections allow different paths through the atmosphere some of which should avoid most of the cloud. Meanwhile geostationary orbits for example are all going to be in a narrow angle in the sky and therefore more vulnerable to local atmospheric interference.
Of note people where still able to use several satellite services.
Single mode fiber optic cable has amazingly high bandwidth. It's hard to compete with that with a radio link. (Though I suppose lasers between satellites could in theory be on par with what you can get from a fiber optic link. On the other hand, with fiber you can run bundles of dozens of strands or more, since the fiber is so cheap relative to the cost of everything else that goes into installing an undersea cable.)
Relying on a single satellite vendor for telecommunications seems kind of sketchy, but then so is relying on a single cable. I suppose the good news here is that places that currently rely on a single source for their connectivity can use satellite as emergency backup, or use the availability of satellite connectivity as leverage when negotiating with telecoms.
> The blackout caused major disruption to aid efforts following the disaster.
Speaking to a friend, apparently they currently use expensive international calls to coordinate efforts, limiting them to audio only.
In terms of immediate issues, they have been struggling to get enough drinking water to the islands as they usually get it from collection systems on the roofs, which are now contaminated.
An internet connection is just one part of the puzzle.
what is the approximate outer diameter of one of those cables? I'm trying to picture in my head how thick the protective layers are, and how large is the joint box
How the cable might break, obviously the pretty small explosion wouldn't break a cable but it might have been the same probable cause of the tsunami, a landslide (which has a lot of energy) -
