Systems and methods for generating a command to monitor communications in a asynchronous transfer mode network are described. The sensor senses at least one physiological characteristic of a patient and is connectable to a monitor that estimates the physiological condition from signals detected by the sensor. A light reflector is arranged outside the first base and in a location corresponding to the first light transmission part, and the first light reflector has a greater strength than that of the first base. Accordingly, if the input device is, for example, a video camera, the video camera is formed only by a CCD, a sample-and-hold circuit for sampling and holding the output from the CCD, an AGC circuit for adjusting the gain of the output from the sample-and-hold circuit, and an AD conversion circuit for converting the analog output of the AGC circuit into a digital output.