The external power supply unit DB-2, built into a powder-coated metal housing, offers space for up to two 12 V / 45 Ah batteries. A connection to the fire alarm control panels IQ8Control and FlexES Control can be made directly via the optional adapter board (part no. HLSPS-ADPTR) with an esserbus® alarm tranponder (part no. 808623). Alternatively, a relay output with floating changeover contact is available for the transmission of faults (mains, battery and collective faults as well as earth fault). DB-2 offers external LED display for operation and collective fault in the lockable front door, internal LEDs for detailed detection of emergency power operation, individual monitoring of battery failure, ground fault, deep battery discharge as well as system errors and mains failure. The settings for battery capacities and combinations are made via DIP switches on the base board of the DB-2.