VSA-S Obsolete Product

Vault Sound Alarm System

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

Where U.L. 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 U.L. listed control unit. The VSA amplifier unit is housed in a tampered steel cabinet with provisions for conduit connections.

The standby battery provides in excess of 80 hours operation in the event of a power failure. An external low voltage plug-in transformer maintains the battery at a fully charged state.

The amplifier unit provides SPDT alarm relay contacts and provisions for 1 to 10 microphones to be connected into the supervised microphone circuit. The VSA contains a DC differential balance control which is adjusted so that the impedance of the external microphone circuit is balanced with the internal impedance of the differential circuit. The VSA will alarm if the external impedance of the microphone circuit increases or decreases.

The microphones are available in surface mount (Model PSM) or flush mount (Model PSM-F). Audio signals detected in the vault enclosure are fed to the amplifier unit where the sensitivity control determines the sound level necessary to alarm the unit.

The Models PSM-T (surface mount) and PSM-FT (flush mount) are microphones with a built-in test sounding device. One PSM-T or PSM-FT must be used in every application.

An alarm indicator light and test switch are provided for system testing by the subscriber. Terminals are provided for remote subscriber and/or central station testing.

The Model APC (Accumulating Pulse Counter) is a plug-in option which allows the system to alarm after receiving a set number of pulses during a 10 minute time frame. The pulse counter has an adjustable range of 1 to 9 pulses.

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