The Bosch VS79055T is an Alarm/Action Relay box designed to allow an operator to activate devices, such as door locks, from a Color Observation system monitor. This unit has all the features of the VS79025T model plus a built-in PIR (passive infrared) motion detector. While both models accept external PIR sensors, having the PIR hard wired to the unit, eliminates the need for an external PIR power supply.
Another advantage of this unit's PIR is its ability to cancel any incoming alarm signals received within 10 seconds of the PIR sensing movement, whereas an external PIR device will cause multiple alarms. In the event of an alarm, this unit will trigger both a visual and audible alert while automatically switching the monitor to display the corresponding camera.