ISO/IEC 9995-1:2009

ISO/IEC 9995 defines a framework for the layout of all alphanumeric and numeric keyboards across the widest spectrum of today's and upcoming applications using keyboards. The functions to be performed by keyboards are grouped into three categories that correspond to the main physical sections of the keyboard.
Application of ISO/IEC 9995 in the design of keyboards will provide the user with a unified, predictable user-machine interface by dividing the keyboard into functional areas and sections and allocating functions to keys.
ISO/IEC 9995-1:2009 identifies the sections of the keyboard and specifies the general shape and relative placement of the sections. Spacing of keys and physical characteristics are covered, as are the principles governing the placement of characters and symbols on keys. ISO/IEC 9995-1:2009 specifies a key numbering system which applies to all types of numeric, alphanumeric and composite keyboards of information technology equipment.