In this circuit, the Elektor ATM18 is in charge of communications and represents the master unit, while the DS18S20 sensors are the slave units. The DS18S20s respond to the orders from the master by sending back to it the temperature they are measuring. Our circuit makes it possible to measure temperatures from ?55 °C to +125 °C (–67 °F to 257 °F) with 9-bit resolution and an accuracy of ±0.5 °C from ?10 °C to +85 °C (14 °F to 185 °F).