Wireless thermometers transmit the measured temperature by radio to a central display unit. Several measuring units can be connected to such a unit outdoors or in different rooms of a building and transmit the measured values to
them. Wireless thermometers offer a relatively wide range of functions. They can be used to measure outdoor and indoor temperatures, and often humidity as well. They offer displays for the maximum and minimum values and can store the maximum and minimum daily values in an internal memory and compare them with new readings. Depending on the design, wireless thermometers can collect readings from multiple sensors
The analogue measured values are digitised by an AD converter and transmitted to the central measuring unit, where they are shown digitally on the display. As far as radio transmission is concerned, two frequency ranges in the sub-gigahertz range are available: the 433 MHz and the 868 MHz bands. The signals can be modulated using various modulation methods such as frequency shift keying or minimum shift ke ying (MSK).