Electric Telegraph
The telegraph was the first device to send messages using electricity. Telegraph messages were sent by tapping out a special code for each letter of the message with a telegraph key. The telegraph changed the dots and dashes of this code into electrical impulses and transmitted them over telegraph wires. A telegraph receiver on the other end of the wire converted the electrical impulses to dots and dashes on a paper tape. Later, this code became universal and is now known as Morse Code.