Newsgroups: sci.electronics.misc Subject: Re: Need help running USB web cam over large distances References: <[email protected]> [email protected] writes: > I'm a PHP web developer working with Linux by day, and I tinker with > side projects at home to see if I can get something off the ground. I > need someone to give me advice on a webcam project where I need to use > wired, not wireless, cameras to build a video surveillance arrangement > that can be used in large offices. I got excited about the idea when I > found out that my office paid $30K for their video surveillance system. > > The first part of this is the wiring of the video cam. I understand > that USB requires repeater extender things to run it over long > distances, and these may require an AC input. But has anyone > experimented with switching the signal to CAT 5 and then putting it > back onto USB again? Shouldn't it then be able to go longer distances? There are some products that claim to be able run USB signals through CAT5 UTP wiring. They go somehow longer distance than normal USB cables, but I don't think they can extend the maximum lengthof USB network. If you really want some longer distance than few meters, I would recommend to use some technology that is designed to work over the needed distance in the beginning, rather than pushing the USB techology that is originally designed for short distances only. Technologies that are suitable for longer distances over CAT5 wiring are webcams with Ethernet interface (normal Ethernet networking limits) and CCTV cameras designed for UTP wiring signal transfer connected to video digitizing card/device on the computer end (works well up to several hundred meters). > Before I start tearing apart a web cam's USB cable in my garage to do > this experiment to see how long the video signal can run with CAT5, I'd > like to know if someone has advice on this. There are real technical reasons why USB cables have their distance limits, and why the cable used with USB devices is different that CAT5 cable. CAT5 cable is not the optimum medium for USB signals... Maybe not worth to take apart an expensive web camera. -- Tomi Engdahl (http://www.iki.fi/then/) Take a look at my electronics web links and documents at http://www.epanorama.net/
