I see those ferrite cores on lots of cables. I have several analog video cables (HD-15 connectors) with them. Since there is a connector on each end of the cable but the core is only on one end, it's not clear the purpose. There doesn't seem to be any instruction as to which end of the cable goes where (computer/monitor). I've always guessed that they were spike protection rather than interference protection -- high voltage that manages to get on the data lines starting, e.g., from the cable / telephone line Internet connection. Is there any credible "official" statement as to their purpose?
Fred Holmes At 04:38 PM 3/3/2008, Tom Piwowar wrote: >>Some of the USB cables I get with appliances also include a graphite >>choke to reduce interference. > >Some Apple keyboards have a ferrite core on the end of the cable that >plugs into the computer. I think that is supposed to limit radiation FROM >the keyboard. Not to keep QRN out of the computer. ************************************************************************* ** List info, subscription management, list rules, archives, privacy ** ** policy, calmness, a member map, and more at http://www.cguys.org/ ** *************************************************************************
