A physiological measurement system has a sensor, a processor, a communications link and information elements. The sensor is configured to transmit light having a plurality of wavelengths into a tissue site and to generate a sensor signal responsive to the transmitted light after tissue attenuation. The attenuated light can be used by the system to determine a plurality of physiological measurements. The processor is configured to operate on the sensor signal so as to derive at least one physiological parameter after which of the plurality of physiological measurements the system is configured to or capable of measuring.