"This SAE Aerospace Recommended Practice (ARP) covers the general design and performance characteristics of illuminated information signs for service in the passenger compartment of passenger transport aircraft. Relating to regulations@ this ARP covers regulations that have been harmonized with the Federal Aviation Administration (FAA) and European Aviation Safety Agency (EASA); if there are any differences@ the applicant should review the appropriate regulations. ""Illuminated information signs"" are lighted signs used to inform occupants of the passenger compartment. Signs may use symbols or letters to convey messages. This ARP does not apply to ""EXIT"" signs@ which are the subject of ARP503."