−−···
// MORSE · DIGIT
The digit 7 in Morse
the digit 7 is coded −−··· — five symbols. One of the regular digits in the system, identical between continental and international Morse.
Memory hook
Two dashes, three dots — mirror of 3.
CW phonetic: say "daa daa di di di" out loud. "di" is short, "daa" is three times longer.