Guideline E: Input and output interfaces


This section of the guidelines reviews design considerations that make it easier to implement multicultural support at the input and output (I/O) interfaces. The primary physical I/O interface to computers consists of the keyboard, display, and printer. Enabling the software alone does not result in a usable product if its physical interface is not enabled as well.

Many versions of the physical interface are required to accommodate the wide variety of scripts and paper sizes that are used throughout the world. If you rank the number of different characters in each language, English would be near the bottom with only 26 different alphabetic characters while Chinese would be at the top with over 100,000 characters. Designing physical interfaces to support English language only is relatively simple. In addition to the primary physical interface, other devices, such as, the mouse, TrackPoint, TouchPad, touch tablets, touch screen, and light pen, have gained popularity over the years. These devices are mostly culturally and linguistically neutral, but not so with the text-to-speech output or voice recognition input devices, which are used in advanced graphical user interfaces, unique user environments, aids for the disabled, and marketing promotions. Despite these advancements, most input and output is performed by keyboard, display, and printer.


The keyboard is the most popular input device. It must support many scripts, and permit the user to easily enter all the characters in each of the supported scripts. Though the keyboard has several groups and levels as discussed later in this chapter, many scripts contain more characters than can possibly be assigned to the physical keys of a keyboard. Modern input interface relies on the use of software Input Method Editors (IMEs) to input characters. The user can use the same keyboard, regardless of the script. Many key strokes may be required to compose a single character.

The international standard for keyboard layouts introduced in 1994, ISO/IEC 9995 Information Technology - Keyboard Layouts for Text and Office Systems, contains more detailed information about keyboard layouts.

Example: The lBM Arabic/French keyboard 462 (PDF,150KB) has one group to enter Latin characters and French accents and another to enter Arabic characters. Both groups support the Unshift and Shift modes (levels) of the keyboard.

Example: Thousands of methods have been invented for entering Chinese characters into computers using a keyboard, with several hundred having been used on computers, and a few commonly accepted by the public. Most of the IMEs are based on either sound or on structure. After typing in the sound of the character or the strokes and radicals of the character, the IME presents a list of all the possible Chinese characters that satisfy the input, and the user selects the correct one.

Example: The IBM Unicode Input Method Editor (IME) provides the facility to input Unicode code points into a Java application. This provides developers and testers with a mechanism to verify that their Java application correctly handles Unicode character data without having a NL environment for a particular language. A similar utility is the IBM Indic IME that can be used to enter Indian scripts directly into a browser on Windows operating systems.

Displays and Printers

A display that can show only English characters cannot be marketed in Europe or Asia. A printer that only accepts North American 8.5-by-11-inch paper is not usable in European countries. Displays and printers must provide multicultural support to accommodate the diversity of characters and paper sizes.