This note describes a resistor network that enables automated linearity checks of resistance-thermometry measurements. The network is made in such a manner that the voltages across any number of resistors in a resistor series are read to get separate four-terminal values interrelated by the formula for the series connection. Linearity tests of resistance bridges show that the network can resolve deviations from linearity down to +/- 20 mu ohm for resistance measurements from 32 to 284 ohm.