Now you can turn heaters, fans, and other devices on or off using the Davis Model 6544 WeatherLink for Alarm Output and your Vantage Pro2 or Vantage Vue Weather Station. The software walks you through the choices quickly and easily—yet the possibilities are almost unlimited! For each of four outputs, you can enter up to eight different weather parameters. Enter threshold values for each, select from nine different test conditions, and link the entries together as you choose. The connector block provides the interface between your weather station and an electrical device. For high-power devices, you may also need to add electrical relays (not supplied by Davis). Connection to a PC is not required except for inital setup.