scope:

This ETS defines the assignment of alphabetic letters to digits on standard telephone keypad arrays. The assignment of characters with diacritical marks, e.g. á, å, c (French), ë, ñ, etc. on the standard telephone keypad array, or the assignment of other non-Latin character sets is outside the scope of this ETS. This ETS applies to all terminals, public and private, that assign alphabetic letters to standard telephone keypad arrays. The standard can be applied to keypad arrays provided in hardware form (e.g. as push button keys) or software form (e.g. as soft keys on a visual display).