The present disclosure relates generally to patient monitoring systems and, more particularly, to a resistance emulator for patient monitors. In an embodiment, a resistance emulator includes a first plug configured to couple with a medical monitor. The medical monitor is configured to receive a calibration resistance value of a medical device sensor from a coded resistor. The resistance emulator further includes a second plug configured to couple with a medical device sensor. The medical device sensor is configured without the coded resistor. The resistance emulator also includes emulation circuitry configured to provide an emulated signal representative of the calibration resistance value to the medical monitor.