Abstract: A miniature portable physiological parameter measuring system with interchangeable sensors. In a preferred embodiment, the system is incorporated into a wrist-worn device having the general configuration of a wristwatch. The device contains, in the upper right-hand quadrant, an outcropping on which a pulse sensor is located. In the lower left-hand quadrant of the device, when worn of the left hand, diagonally opposite from the sensor described above, there is positioned a tiny plug. When the plug is removed, an open area is displayed which allows for the introduction of a connector in the wrist device. On introduction of the connector into the side of the device, the permanent sensor housed within the wrist device is disconnected and the remote sensor commences inputting a signal into the wrist device.