The emergency lights, which are integrated in the escape slides of the passenger/crew doors, are turned on automatically when the escape slides are deployed.For the A340-600, the offwing escape-slide system is installed at the overwing emergency-exits, and is electrically operated. Deployment of the escape-slide is automatic when the door is opened with the escape-slide control handle set in the ARMED position. The battery bus bar supplies 28V DC power to operate the electrical escape-slide release system via the Slide-Release Power-Supply Unit (SRPSU).