Going Postal by Terry Pratchett is a story involving a competition between a traditional post office and a light-based telegraph system called "clacks." You might enjoy the book and/or television adaptation.

After his death a few years ago, an idea from the book was actually implemented on the internet and is the reason you see "GNU Terry Pratchett" around.[0][1]

[0] https://www.theguardian.com/books/shortcuts/2015/mar/17/terr...

[1] https://www.reddit.com/r/discworld/comments/2yt9j6/gnu_terry...