For the purposes of this International Standard, a portable computer is defined as a computer with a screen and an attached keyboard that is capable of running on battery power for extended periods of time and is relatively easy to transport from one location to another by a single individual. This International Standard gives design guidance for product designers; this International Standard indicates those requirements and recommendations contained in ISO/IEC 9995 and ISO 9241-4:1998 that are to be considered in designing portable computers keyboards. This International Standard strives to maintain consistency, as far as practical, between keyboards for portable computers and desktop computers. To accomplish this goal, this International Standard has reviewed ISO/IEC 9995 and ISO 9241-4:1998 to identify those design features of these two base standards which are to be followed, which are exempted from this International Standard and which are permitted variations. This International Standard is intended primarily to apply to full size portable keyboards (e.g. A4). It may also apply to other keyboards outside this scope. ISO 9241-4 contains a proposed alternative method for conformance by a test based on user performance and subjective rating scales. This International Standard consists of two major categories of guidelines for portable computers: 1. Layout characteristics 2. Physical (ergonomic) characteristics