key-book
key-clicks
key-disk
keyed
keyed-bar
key-entry
keyer
keyframe
keyhole
key-in
  keying
keying-fit
key-joint
key-light
key-lock
key-opening
keypad
key-pulse
keypunch
keyseat
keyseater

    keying signal

     телеграфный ключ

     сигнальная клавиша