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

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.