Abstract: The present invention is directed to improve the convenience and comfort of the shooting site. According to the present invention, an adapter for an optical transmission system for optically transmitting analog video signals, digital video signals, control signals, audio signals, or a combination thereof between a pair of the adapters, wherein when the pair of the adapters are used with optical multiplexer/demultiplexers provided on both of the adapters, the optical multiplexer/demultiplexers being used to transmit the signals with multiple frequencies such as CWDM or DWDM through a single optical cable, at least one of an internal reflectance of the optical cable and light intensity in multiple frequency bands can be displayed on the display part.

Abstract: The present invention provides an optical transmission system for optical transmission of a signal between a first and a second adaptors, wherein the first and the second adaptors each include an input terminal, a determination unit, and a display unit, a first signal is input to the input terminal, the first signal being an analog video signal or a digital video signal, the determination unit is configured to determine whether the first signal is the analog video signal or the digital video signal and to determine a type of the digital video signal when the first signal is the digital video signal, and the display unit is configured to display information obtained in determination by the determination unit.