The GKOS keyboard principle         

The GKOS keyboard has 6 keys (3 for each hand) located on the back of the device, each representing one of the letters from A to F. Simultaneously pressing two keys on one hand produces the letters G, K, O, S and W. Other letters (next ones in the alphabet) are produced by pressing one key with the other hand while one of these combinations is held down.

Other combinations of keys produce different functions such as space and backspace. Pressing all six keys at once toggles between letters mode and numbers mode (which operates similarly). The thumbs can be used to control the mouse functions on the front panel by using e.g. a Pointing stick-type device. Consequently, most of the front panel can be reserved for the display.

As the GKOS typing system is unfamiliar to most people, there is a learning curve before considerable text entry speeds can be reached. But with practice, speeds of 50 WPM (= 250 characters per minute) have been reported. Practical limit has been estimated to be around 60 WPM based on studies made on other physical two-hand chording keyboards.

The GKOS keyboard is intended for replacing the QWERTY where there is not enough room for a large number of keys but still all PC keyboard functions are required. It has not been used in commercial applications except Crichton barcoding audio PDAs. There is, however, software for trying this concept on the PC keyboard using keys sdf/jkl, and there are instructions and software available for building small GKOS devices based on PIC and Atmel (Arduino) microcontrollers.

A GKOS chording keyboard application development for touch screens was started on the GKOS Google Group on May 25, 2009. Then, on May 8th, 2010, a GKOS iPhone application and on October 3rd, 2010 an Android GKOS application became available where you can type on GKOS keys on the touch screen with your thumbs.

GKOS is an open standard, meaning anybody is free to manufacture and use it, and it does not include any intellectual property rights by the inventor. The concept has been presented at ITU-R as an example of possible future text entry methods. GKOS became public domain in October 2000.

The main GKOS website:
The GKOS builders' site:

Page created by S.Tiainen 4 June 2008
- last edit 27 Mar 2011