This standard applies to external and internal audiovisual communication of passenger information, destination/trip information, and announcements related to safety and emergencies, as well as advertisement/community information for rail transit vehicles. It specifies the physical, logical, and electrical interfaces of the passenger information system for rail transit vehicle systems and subsystems. This includes the following equipment: passenger information signs,public address system, passenger/crew call intercom system, internal display system, and radio system interface with the public address system.