Chorded keyboard

A secondary advantage is that it can be built into a device (such as a pocket-sized computer or a bicycle handlebar) that is too small to contain a normal-sized keyboard.

Due to the small number of keys required, chording is easily adapted from a desktop to mobile environment.

Thad Starner from Georgia Institute of Technology and others published numerous studies[2][3][4] showing that two-handed chorded text entry was faster and yielded fewer errors than on a QWERTY keyboard.

The earliest known chord keyboard was part of the "five-needle" telegraph operator station, designed by Wheatstone and Cooke in 1836, in which any two of the five needles could point left or right to indicate letters on a grid.

[citation needed] Some early keypunch machines used a keyboard with 12 labeled keys to punch the correct holes in paper cards.

When Louis Braille invented it, it was produced with a needle holing successively all needed points in a cardboard sheet.

[6] The Perkins Brailler, first manufactured in 1951, uses a 6-key chord keyboard (plus a spacebar) to produce braille output, and has been very successful as a mass market affordable product.

After World War II, with the arrival of electronics for reading chords and looking in tables of "codes", the postal sorting offices started to research chordic solutions to be able to employ people other than trained and expensive typists.

[9] In a famous 1968 demonstration,[10] Engelbart introduced a computer human interface that included the QWERTY keyboard, a three button mouse, and a five key keyset.

In the early 1980s, Philips Research labs at Redhill, Surrey did a brief study[citation needed] into small, cheap keyboards for entering text on a telephone.

INTERCHI '93 published a study by Matias, MacKenzie and Buxton showing that people who have already learned to touch-type can quickly recover 50 to 70% of their two-handed typing speed.

It is implemented on two popular mobile phones, each provided with software disambiguation, which allows users to avoid using the space-bar.

Multiambic keyers are similar to chording keyboards but without the board, in that the keys are grouped in a cluster for being handheld, rather than for sitting on a flat surface.

Chording keyboards are also used as portable but two handed input devices for the visually impaired (either combined with a refreshable braille display or vocal synthesis).

In some applications, the spacebar is used to produce additional chords which enable the user to issue editing commands, such as moving the cursor, or deleting words.

Note that the number of points used in braille computing is not 6, but 8, as this allows the user, among other things, to distinguish between small and capital letters, as well as identify the position of the cursor.

Their first commercially available device is the CharaChorder One, which features a split design with each having access to 9 switches that can be moved in five directions (up, down, left, right, and pressed) in contrast to typical keyboards.

Another early commercial model was the six-button Microwriter, designed by Cy Endfield and Chris Rainey, and first sold in 1980.

Its key combinations were based on a mnemonic system that enabled fast and easy touch type learning.

The unique design also gave a relief from hand stress (Carpal Tunnel Syndrome) and allowed longer typing sessions than traditional keyboards.