To provide a remote operating device which can make a video processing unit judge the difference of signaling route, a video processing unit which can judge the difference of signaling route from the remote operating device, and a transmission/reception system which can judge the difference of signaling route from the remote operating device to an operated device.

The transmission/reception system comprises a remote operating device 200 and a video processing unit. The remote operating device 200 is provided with a light emitting element LD. The video processing unit is provided with an infrared signal light receiver 307. An infrared signal outputted from the light emitting element LD of the remote operating device 200 is received by the infrared signal light receiver 307 of the video processing unit. The light exit surface of the light emitting element LD has such a plane shape as not becoming line symmetric to any axis on the surface.

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