PS 6648 is a power supply unit suitable to get continuity power for EN 54-16 systems units like DXT 9000 and DXT 7000, and relevant complementary devices in case of mains power supply interruptions. It includes recharging and monitoring functions for the lead-acid batteries connected to it. It must be equipped with batteries with suitable capacity, dimensioned according to the system power absorption and to the evacuation requirements. According to EN 54-16 standard, PS 6648 shall be installed into the same rack cabinet where there is the audio system with emergency purposes (or a system part) to which it is connected.