This document defines the following elements for urban rail rolling stock: the functional requirements for a communication device between passengers and driver or Operations Control Centre (OCC); the dynamic behaviour of the Communication device. This document is applicable to the categories I to III of Urban Rail rolling stock defined in CEN/CLC Guide 26: (I) Metros; (II) Trams; (III) Light Rail. NOTE 1 CEN/CLC Guide 26 defines Metro, Tram and Light Rail as public transport systems permanently guided at least by one rail, intended for the operation of local, urban and suburban passenger services with self-propelled vehicles and operated either segregated or not from general road and pedestrian traffic. This document applies to rolling stock both with and without driver. NOTE 2 The communication device is different from the PAS, but it can share some parts of the PAS to achieve its functionalities. NOTE 3 The PAS is regarded as a safety relevant system whereas communication device is non-safety relevant aid to passengers.