ISO/IEC 9995 Information technology — Keyboard layouts for text and office systems is an ISO standard defining layouts of computer keyboards. It defines a keyboard as having three groups of key assignments:
The ISO/IEC 9995 standard dates to 1994 and has undergone several updates over the years. It consists of the following parts:
(ISO 9995-6:2006 Function section was withdrawn 2009-10-08.[8])
ISO/IEC 9995-3:2010[9] defines a common secondary layout ("common secondary group") for the alphanumeric keyboard. These are engraved on the right part of the keytops; the standard defines their position independent of the characters of the primary layout. Thus, e.g. the Yen symbol »¥« occupies the shifted position on the 6th letter key of the second row, whether this is the Y key on an QWERTY keyboard (like the USA layout) or the Z key on a QWERTZ keyboard (like the German layout).
Alternatively, the standard defines an "outdated common secondary group" for compatibility purposes only. This resembles the "common secondary group" defined in the earlier edition of the standard, ISO/IEC 9995-3:2002.
The diacritical marks contained in the common secondary group act as dead keys, i.e. they are to be entered before the base characters they apply to. Thus mechanism is also to be used for sequences of more than one diacritical marks, to wrile languages like Vietmanese and Navajo.
Moreover, ISO/IEC 9995-3:2010 defines a list of "Peculiar Characters which can be entered as combinations using diacritical marks". This list specifies combinations of a diacritical mark and a second key. E.g., symbols like the not-equal sign »≠« (Unicode U+2160) can be entered this way. Especially, letters with a horizontal stroke (like Croatian Đ/đ, Maltese Ħ/ħ, or Comanche Ʉ/ʉ) are entered this way using the "horizontal stroke accent" located on the K key.
ISO/IEC 9995-8:2009 defines an assignment identical to E.161 of the 26 letters A–Z to the number keys of a numeric keypad. The space character is not assigned.