Telegrams were part of The Adventures of Captain Proton holoprogram created by Tom Paris. In the program, they were received as a strip of paper with the message printed on it for the intended recipient. Each sentence was concluded with the word "stop".
While in the program, he received a telegram in his rocket ship from the Earth government. It stated that aliens from the fifth dimension were at war with Doctor Chaotica and his Army of Evil. (VOY: "Bride of Chaotica!")