The Bosch LBC1402/10-US Rotary 5-Step 12W Volume Control can be used to adjust the zone level locally. The volume control utilizes a power-saving, 4-wire volume override, where the override relay is activated during an emergency call. In the event of an announcement, the built-in relay ensures that the message is broadcast at a preset level, independent of the local volume setting. Ease of installation, operation and reliability are optimized in the design. The total load of the loudspeakers connected to the volume control may not exceed the rated power.