The famous message sent in Morse code May 24, 1844; we guess it started dot-dash-dash
Morse on May 24, 1844, over an experimental line 
from Washington, D.C., to Baltimore, the message said: "What hath God wrought
... [DOC] [TLE] Morse Transmits the First Message by Morse Code (May 24, 1844 ... [PAR] On May 24, 1844 Samuel F. B. Morse transmitted the first message on a United ... 
using the Morse code that became standard in the United States and Canada.