However, one listing of common abbreviations compiled in 1859 includes 1 1 (dot dot, dot dot) for I AM READY; G A (dash dash dot, dot dash) for GO AHEAD, S F D for STOP FOR DINNER; G M for GOOD MORNING.
Tom Standage
However, one listing of common abbreviations compiled in 1859 includes 1 1 (dot dot, dot dot) for I AM READY; G A (dash dash dot, dot dash) for GO AHEAD, S F D for STOP FOR DINNER; G M for GOOD MORNING.