The industry is rapidly adopting USB 3.0 as a data interface technology for industrial and scientific cameras. One question I get all the time is about the maximum cable length possible with USB 3.0. Despite all the media coverage around USB 3.0 technology there are still perceptions that USB 3.0 is limited to 3 or 5 meters, which is not the case. Distance of 10, 15 and even 20 meters are possible with USB 3.0 using active cables. Using bus extender technology, distances of 100 to 200 meters are possible.
Active cables are often nothing more than a simple cable with signal conditioning electronics built right into the cable while bus extender solutions are more cumbersome. The signal conditioning circuitry found in active cables does not differ greatly from that found in other high-speed data interfaces, but in the case of USB 3.0 the signal conditioning resides in the cable as opposed to the inside of end point devices. The obvious benefit is that in situations where long distances are not required, devices do not have to bear the cost of the signal conditioning electronics, thus a more cost-effective solution. The second benefit of having the signal conditioning right in the cable is that it can be tailored to the precise length of the cable for most accurate performance.
I was at VISION Stuttgart in early November. I was approached by a gentleman who worked for a cable manufacturer to discuss USB 3.0 cables and introduce me to his new product offerings. In a flash, he pulled out a 14 meter, bus-powered USB 3.0 active cable where no external power supply required. Always ready for the unknown, I was able to pull out a spare USB 3.0 camera and challenge him to test the cable right there on the show floor. Accepting the challenge, we loaded the camera driver and demo application onto his laptop, plugged in his 14-meter cable, connected the camera and started the application. In less than 4 minutes we had our high-speed USB 3.0 camera working at the full 5 Gbps speed of the USB 3.0 interface over a 14-meter cable, streaming 4 megapixel images at 90 frames per second without a single hick up. Literally a plug-and-play solution with long distance capabilities and ease-of-use. That was certainly one of the show highlights for me!