Modulated continuous wave

Abbreviated "MCW".

"MCW uses a fixed audio tone to modulate a carrier wave."[1]

Instead of use on-off to form the dit-dah's of Morse code, MCW turns a tone on and off.

Classification of transmission modes

A1	Continuous wave (CW)
A2	Modulated continuous wave (MCW)
A3	radiotelephone; voice

• Radio equipment on NR16020