Did you know that the early telegraphs used one wire for each letter of the alphabet, no one ever considered a code for each letter. The most expensive part of telegraph letters were the wires because of this. In 1774, the Telegraph used 24 wires!! Now thats a lot of wires.
Allesandro Volta, had created the early battery in the 1800s which the telegraph then used to pull the receiver whenever an electric pulse passed. This was able to detect the flow of electricity from the metal plate dropping from the battery. This made sounds to vocalize the letters of the alphabet. The letter A would be 1 bleep and the letter H would be 8 bleeps, the bleeps correspond with the number of each letter in the alphabet, now imagine trying to fully understand what someone is trying to transmit in beeps… Especially if they used the letter Z.
The Telegraph would be considered digital. It included binarly-like signals, encoding and no analog variation