This standard is applicable to all kinds of equipment with numeric input used in homes, for example videotex terminals, household appliances, climate control and remote controls for TV, for recorders and for lights; excluding telecommunication terminals, data processing equipment and office machines, subject to CCITT E.161 and ISO 3791. This standard specifies a layout for numerical keyboards with three rows of three keys each and a fourth row with at least one key. The layout described in this standard is concerned only with the nominal relative positions of keys; it is not intended to define physical factors, such as keyboard slope, size and shape of keytops, nor the way in which the keytops are inscribed. The definition of such physical factors may be the subject of other standards.