The Vehicle Monitor receiver can be located in the house, office or work shop and plugged into any standard wall outlet. The weatherproof outside transmitter, operated by 6 AA batteries, should be located in the area of the driveway. The probe is attached to the transmitter with 50 feet of direct burial cable and should be buried alongside the driveway with the transmitter box mounted on a tree or post about 4 feet high. The Vehicle Announcer probe will detect the movement of a metal object such as a car coming up the driveway. The transmitter will then send a radio signal up to 4 miles back to the receiver to activate the voice recording. The voice alert has a volume control and identifies which transmitter was activated if more than one is being used. The receiver is also equipped with a relay output to operate any of our Driveway Monitor accessories shown below. You may also add the MURS MAT InfraRed Transmitter to this system to protect areas where it is necessary to detect people walking. Up to four transmitters may be used with each system.