Communication system, transmission device, reception device, communication method, program, and communication cable

A communication system comprising:

• a transmission device configured to transmit pixel data of one screen worth of an uncompressed image to a reception device in one direction within a valid image section that is a section obtained by removing a horizontal retrace section and a vertical retrace section from a section from one vertical synchronizing signal to the next vertical synchronizing signal, using a first differential signal;
• and
• a reception device configured to receive said first differential signal transmitted from said transmission device;
• wherein said transmission device includes
• first conversion means configured to convert data different from said pixel data, which is data to be transmitted, into a second differential signal made up of a first partial signal and a second partial signal, transmit said first partial signal to said reception device via a first signal line, and also output said second partial signal,
• first selecting means configured to select one of a transmission signal that is a signal relating to control, and said second partial signal output from said first conversion means, and transmit the selected signal to said reception device via a second signal line,
• first control means configured to control, in the case of transmitting said transmission signal to said reception device, said first selecting means so as to select said transmission signal, and in the case of transmitting said second differential signal to said reception device, to control said first selecting means so as to select said second partial signal, and
• first decoding means configured to receive a third differential signal transmitted from said reception device, and decode this to the original data;
• and wherein said reception device includes
• second conversion means configured to convert data different from said pixel data, which is data to be transmitted, into said third differential signal, and transmit this to said transmission device,
• second decoding means configured to receive said second differential signal transmitted from said transmission device, and decode this to the original data,
• second selecting means configured to select one of said transmission signal and said second partial signal, and
• second control means configured to control, in the case of receiving said transmission signal, said second selecting means so as to select and receive said transmission signal, and in the case of receiving said second differential signal, to control said second selecting means so as to select said second partial signal, and said second decoding means so as to receive said second partial signal.