ITU-R M.1677-1 Morse Code Technical Specification
How Easy Morse Code Translator implements international telegraphy timing standards and audio signal generation.
1. Core Timing Ratios
Recommendation ITU-R M.1677-1 establishes the international standard for Morse code transmission across radio and wired systems. Under this standard, all temporal intervals are calculated relative to a single fundamental unit known as the dot duration (t).
1 Dot (Dit) = 1 time unit (t)
1 Dash (Dah) = 3 time units (3t)
Intra-character space = 1 time unit (1t)
Inter-letter space = 3 time units (3t)
Inter-word space = 7 time units (7t)
2. Words Per Minute (WPM) Formula
Morse speed is defined using the standard reference word PARIS. The word PARIS consists of exactly 50 dot-units (including internal gaps and trailing inter-word spacing).
Dot Duration (ms) = 1200 / WPM
At 20 WPM, a single dot lasts 1200 / 20 = 60 ms, a dash lasts 180 ms, inter-letter gaps span 180 ms, and word gaps span 420 ms.
3. Procedural Signals (Prosigns) & Q-Codes
In addition to standard letters and numbers, radio operators use procedural signals (prosigns) transmitted without inter-letter pauses:
- SOS (
...---...) - Distress signal - AR (
.-.-.) - End of message - SK (
...-.-) - End of contact - BT (
-...-) - Paragraph break