Patent ID: 7352967

Claim:
A data transmission system comprising: a plurality of subscriber units including at least a subscriber unit with a video receiver and a subscriber unit without a video receiver, each of the plurality of subscriber units is configured to interconnect with a central office unit via optical fibers, the central office unit is configured to multiplex a video signal with signals other than the video signal and to deliver them to the plurality of subscriber units, wherein each subscriber unit is configured to demultiplex a received signal, and the subscriber unit without the video receiver includes a first wavelength division multiplexer/demultiplexer configured to attenuate a particular wavelength signal, the subscriber unit with the video receiver is configured to separate the video signal from the multiplexed signal received at a second wavelength division multiplexer/demultiplexer and to input the video signal to the video receiver, and wherein the subscriber unit without the video receiver is configured to separate the video signal from the multiplexed signal received at the first wavelength division multiplexer/demultiplexer, to attenuate the video signal without a terminator to prevent further downstream transmission of the video signal with respect to the first wavelength division multiplexer/demultiplexer, to separate the signals other than the video signal, and to input the signals other than the video signal to a transmitting and receiving section, and the subscriber unit without the video receiver includes a transmitting laser diode and a receiving photodiode, the transmitting photodiode is disposed outside of the first wavelength division multiplexer/demultiplexer and on a first end surface of the first wavelength division multiplexer/demultiplexer, and the receiving photodiode is disposed outside of the second wavelength division multiplexer/demultiplexer and on second end surface, opposite the first end surface, of the first wavelength division multiplexer/demultiplexer.