The VSA series is a self-contained sound detection system listed by Underwriters Laboratories, Inc. for the primary protection of reverberant and non-reverberant vaults, such as bank and mercantile vaults.

The VSA system contains a microprocessor driven DC differential balance control which is adjusted so that the impedance of the microphone circuits are balanced with the internal impedance of the differential circuit. The VSA will alarm through it's SPDT alarm relay contacts if the microphone circuit impedance increases or decreases.

The main controller and the microphone are combined into a single enclosure (VSA-1).

The main controller utilizes a single button for system balancing. The on-board accumulator allows the system to alarm after receiving a set number of pulses during a 10-minute time frame. The accumulator has an adjustable range of 0 to 9 pulses.

Sensitivity is manually adjustable to detect all attacks as set forth in UL 639 and UL 681.

The on-board test button and sounder provide a means to manually test the system during system inspection.

The Remote Test Annunciator (RTA) can be installed in a remote location, likely by the alarm control panel. The RTA allows for remote testing and it annunciates the system condition with LED's.

The optional self-test feature validates the system's performance. This feature enables the user to be informed of possible system degradation, due to severe environmental changes, before finding out too late.

The VSA will integrate and may be powered by any alarm control panel.

The VSA-2K is a kit consisting of one (1) VSA-1 Controller/Microphone, one (1) VSM microphone, and one (1) RTA remote test annunciator. Coverage can be expanded by adding eight (8) additional VSM microphones for a total of ten (10) microphones, including the VSA-1 control unit/microphone.

Where UL certification is required, the VSA system must be installed in compliance with U.L. 681. Including at least one manual-initiating device in the vault and connection of the VSA to a UL listed control unit.