The B200SR-LF-WH and B200SR-LF-IV sounder bases are used with addressable detector heads. Refer to the appropriate manual for more information on sensors. The B200SR-LF-WH/B200SR-LF-IV low frequency sounder base generates a low frequency tone around 520 Hz. Studies have shown that low frequency audible devices that operate around 520 Hz are more effective in waking individuals in sleeping areas. It offers maximum flexibility in configuration and operation to meet or exceed the requirements of UL268 and UL464. The sounder base is capable of producing either the distinctive three-pulse temporal pattern (ANSI Temporal 3) fire alarm signal now required by NFPA 72 for commercial and residential applications or a continuous tone by simply removing the included jumper from the device. Additionally, the B200SR-LF-WH/B200SR-LF-IV is designed to be compatible with existing installations of B501-Series sounder bases. The sounder base is intended for use with intelligent systems. The sounder base requires an external 24 VDC power supply. The connections for the external power supply and the communication loop are isolated to prevent electrical interaction between them. Refer to the panel manual for maximum allowable number of units per loop.