With the installation of this USB thermometer, compatible Vigor routers can take continuous temperature readings from the vicinity of the router. This USB thermometer connects to the router\'s USB port either directly or placed nearby using the supplied 1 Metre USB extension cable. You can log into the router at any time and see the current temperature and the previous 24-hour\'s high/low as well as graphs. You can set thresholds so that if it gets too hot or too cold at the sensor, you\'ll receive an email or SMS (text message). Typical applications will be to report the temperature in your comms/IT cabinet or room, but also the general office temperature, depending on the placement of the temperature \'dongle\'. USB typically allows a maximum cable length of up to 3M. Note : Exact facilities vary by router model.