The Optical Beacon Transmitter has to be placed on the trackside to mark laps. Ensure the infrared receiver eye faces the side of the track where the Beacon has been placed, otherwise the system will not record lap time. The Beacon transmitter is powered using 8 AA batteries or an external 12V power cable. If you are using 8 AA batteries, unscrew the back cover of the Beacon transmitter and place the battery pack into the transmitter casing. The transmitter has two operating modes: Low power and High power. The Low Power Mode has to be used when the track is less than 10 meters wide, while the High Power mode has to be used when the track is wider than 10 meters. This function is activated by opening the Beacon transmitter with a corkscrew and placing the clip (located directly below where the battery pack is attached to the beacon transmitter board) either over one of the two connectors (for low power mode) or over the two connectors (for high power mode). When the Beacon transmitter operates on high power mode, both the power led lights will light up when the transmitter is turned on. Please, take note that, in High Power Mode, the transmitter has to be powered by an external 12 Volts battery.