The Maxim/Dallas DS1822 is a "1-wire" digital thermometer. Data is read out over the 1-Wire (single wire data/power connection, plus ground) bus. The device has an accuracy of ±2°C over a -10°C to +85°C range. Full range of -55°C to +125°C (-67°F to +257°F)
Multiple DS1822 devices can be attached on the bus and addressed by the device's unique 64-bit serial number. Used with the U401 or U421 the DS1822 can provide remote temperature monitoring/measurement.