General Description
The B501BHT sounder base is used with System Sensor 200 and 500 Series sensor heads. Refer to the appropriate manual for more information on sensors.

The B501BHT incorporates the distinctive three-pulse temporal pattern fire alarm evacuation signal now required by NFPA 72 for commercial and residential applications.

The sounder base is intended for use with intelligent systems. Refer to the panel manual for the maximum allowable number of units per loop. The sounder base requires an external 24VDC supply with reverse polarity capability. The connections for the external supply (terminals 1 and 2) and the communication loop (terminals 3 and 4) are isolated to prevent electrical interaction between them.

When the sensor’s visible LEDs are latched on for approximately 10 seconds, the associated horn sounds. A loop of horns can be made to sound by reversing the polarity of the external supply.

NOTE: When not used as a supplementary evacuation system, the external 24 VDC supply shall be treated as a component of the main power supply system and shall fall under the requirements of the main power supply system per NFPA 72.

Horn Grouping
UL has approved horn grouping for up to six B501BHT base with horn units. When wired as a group, any detector in the group that has its LED’s latched on by the panel will cause other B501BHT units in the group to sound. Grouping is accomplished by wiring the grouped devices together using terminal 5, Sounder Base Interconnect, as shown in the diagram. Since the grouping is not supervised, the groups can only be used for supplementary signaling.

NOTE: Grouping horns together can only be used as a supplementary evacuation system. It is not acceptable to group horns for primary alarm signaling. 

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