CONTINUOUS-WAVE MODULATION is the basic form of rf communications. It is essentially
on-off keying of an rf carrier.
HAND-OPERATED and MACHINE KEYING are two types of cw keying. PLATE, CATHODE,
and BLOCKED-GRID KEYING are circuits commonly used in hand-operated and machine keying.
KEYING RELAYS are used for safety and to handle the current requirements in high-power