The history of HDMI AOC

HDMI cables are usually used to connect audio-visual equipment to TVs and monitors, so most of them are short-distance transmissions, usually only 3 meters long. What should users do if they need more than 3 meters? If you continue to use copper wire, the diameter of the copper wire will become larger, it will be difficult to bend, and the cost will be high. Therefore, the best way is to use optical fiber. The HDMI AOC optical hybrid cable product is actually a technically compromised product. The original intention during development was that all HDMI 19 cables should be transmitted through optical fiber. This is the real optical fiber transmission HDMI, but because of the low-speed channel 7 It is difficult to encode and decode low-speed signals using VCSEL+multimode fiber optic cable. So the developers simply use VCSEL+multimode fiber optic cable to transmit the 4 pairs of TMDS channels in the high-speed signal. The remaining 7 electronic wires are still directly connected using copper wires. It was found that after using optical fiber to transmit high-speed signals, due to the extended TMDS signal transmission distance, optical fiber HDMI AOC can be transmitted to a distance of 100 meters or even longer. Optical fiber HDMI AOC hybrid cable still uses copper wires for transmission of low-speed signals. The problem of high-speed signals has been solved, but the problem of copper cable transmission of low-speed signals has not been solved. Therefore, various compatibility problems are prone to occur in long-distance transmission. All of this can be completely solved if HDMI, an all-optical technology solution, is used. All-optical HDMI uses 6 optical fibers, 4 of which transmit high-speed TMDS channel signals, and 2 of which are used to transmit HDMI low-speed signals. An external 5V power supply is required at the RX display end as the excitation voltage for HPD hot plugging. After adopting the all-optical solution for HDMI, the high-speed TMDS channel and the low-speed DDC channel are all changed to optical fiber transmission, and the transmission distance is greatly improved.