A system for sensing a physiological parameter in a human or animal, and storing a processed sensing signal at a sensor with which the sensing was performed. The system includes a physiological sensor adapted to output a sensor signal representative of a sensed physiological parameter, for processing by a remote processor. A microcontroller has memory, and is located locally to the sensor and is fixedly attached to or housed together with the sensor. An authentication algorithm is stored in the memory and the microprocessor is configured to engage in an authentication process to authenticate the sensor when queried by a remote processor. The memory is configured to receive and store data representative of a sensed physiological parameter after data from the sensor has been processed by a remote processor. The microcontroller may be configured to communicate with a remote processor over a single wire by, for example, using a single wire protocol.
