Half-keyboard
A half-keyboard is a specially designed and programmed keyboard used in limited space situations or when the typist needs a hand free to answer the phone, hold documents, etc. The "Half-QWERTY" keyboard, invented by Edgar Matias, consists of only the left-hand half of a normal QWERTY keyboard, but when the space bar is held down, it switches to the right half of the keyboard, allowing a person to type with only one hand.