Morse Code Encoder Decoder

About Morse Code

Morse code is a character encoding scheme that represents letters and numerals as sequences of two signal durations: dots (short pulses) and dashes (long pulses). Originally developed for telegraphy, it remains in use for amateur radio, aviation navigation, and emergency signaling.

Morse Code Timing Standards

Morse code uses a precise timing system based on the dot duration as the fundamental unit:

Complete Morse Code Character Reference

Morse Code Numerals

Common Prosigns and Abbreviations

Encoding and Decoding Algorithm

JavaScript Morse Code Implementation:

// Character mapping table
const MORSE_CODE = {
  'A': '.-',    'B': '-...',  'C': '-.-.',  'D': '-..',
  'E': '.',     'F': '..-.',  'G': '--.',   'H': '....',
  'I': '..',    'J': '.---',  'K': '-.-',   'L': '.-..',
  'M': '--',    'N': '-.',    'O': '---',   'P': '.--.',
  'Q': '--.-',  'R': '.-.',   'S': '...',   'T': '-',
  'U': '..-',   'V': '...-',  'W': '.--',   'X': '-..-',
  'Y': '-.--',  'Z': '--..',
  '1': '.----', '2': '..---', '3': '...--', '4': '....-',
  '5': '.....', '6': '-....', '7': '--...', '8': '---..',
  '9': '----.', '0': '-----'
};

// Create reverse mapping for decoding
const REVERSE_CODE = Object.fromEntries(
  Object.entries(MORSE_CODE).map(([k, v]) => [v, k])
);

// Encode text to Morse code
function encodeToMorse(text) {
  return text.toUpperCase()
    .replace(/[^A-Z0-9\s]/g, '')  // Remove non-alphanumeric
    .split('')
    .map(char => {
      if (char === ' ') return '/';  // Word separator
      return MORSE_CODE[char] || '';
    })
    .join(' ')
    .replace(/\s*\/\s*/g, ' / ');  // Clean word separators
}

// Decode Morse code to text
function decodeMorse(morse) {
  return morse.trim()
    .split(/\s+/)  // Split on whitespace
    .map(symbol => {
      if (symbol === '/') return ' ';  // Word separator
      return REVERSE_CODE[symbol] || '';
    })
    .join('');
}

// Usage examples:
encodeToMorse('HELLO');      // ".... . .-.. .-.. ---"
encodeToMorse('HELLO WORLD'); // ".... . .-.. .-.. --- / .-- --- .-. .-.. -.."
decodeMorse('.... . .-.. .-.. ---');  // "HELLO"
decodeMorse('... --- ...');           // "SOS"

Speed and Timing Calculation

Morse code speed is measured in words per minute (WPM), using the standard word "PARIS" as reference:

The word "PARIS" contains exactly 50 dot/dash elements (including intra-letter spaces). At 20 WPM, one minute contains 20 × 50 = 1000 elements, so each element is 60000/1000 = 60ms.

Special Characters and Extensions

Common Use Cases

• Amateur Radio: CW (continuous wave) communication between ham radio operators worldwide
• Aviation: VOR navigation beacons and NDB stations transmit identifiers in Morse
• Emergency Signaling: SOS and other distress signals using light, sound, or radio
• Education: Teaching encoding/decoding concepts and digital communication fundamentals
• Accessibility: Assistive communication for people with limited motor control
• Historical Research: Decoding historical telegraph and radio messages

Morse Code Transmission Methods