Yasumi Ushikubo: System for RF communication between a computer and a remote wireless data input device. Mitsumi Electric, Frohwitter Patent und Rechtsanwalte, August 11, 1998: US05793359 (260 worldwide citation)

A wireless data input device requiring no cable for connection to the keyboard or to the pointing device. A wireless keyboard 16 incorporating a pointing device has a data encoder 21 and an RF transmitter 22, and transmits the key data and the pointing cursor data to the reception unit 3 which is co ...