alphanumeric keyboards are described for use with one hand to enter data . each keyboard includes a plurality of individually movable alphanumeric keys that are each assigned a different letter of the alphabet . the keys are positioned side - by - side in multiple rows such that when four fingers of one hand are positioned over a home position , these fingers can depress all the letters by moving less than three key positions from the home position . specialized key features are provided on the keyboard to facilitate the execution of multi - key combinations . a right - hand keyboard and a left - hand keyboard are disclosed as interchangeable with a conventional keyboard in a supporting shell . alternatively , both the right - hand and left - hand keyboards are supported on opposite sides of a common rotatable member pivotably mounted in the supporting shell .