FSJoin™ is a programming compatibility feature of Federal Signal’s light bars and exterior/interior warning lights that work in conjunction with Pathfinder® light/siren controllers. This feature enables the synchronization of functions, operation, and flash patterns of individual light heads from multiple warning devices to create a unified vehicle solution. FSJoin further provides the capability to synchronize warning lights on multiple “like-programmed” vehicles to unify the visual and audible warning of a multi-vehicle response.