ISO/IEC 9995-10:2013

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 9995-10:2013 describes conventional symbols and methods to represent graphic characters not uniquely recognizable by their glyph on keyboards and in documentation.