Steven, USB does not drive data onto a cable that has no device attached, so a test with only cables attached is not valid.
These days most new USB devices are USB 2, so you need USB 2 devices and should mix older USB devices for perhaps 2 ports for the older data rate. IMO I don't see any need to test the lower data rate on the main port of the hub if you test other hub ports at both data rates. Typical peripherals such as a USB hard drive, a printer, keyboard, and mouse should satisfy emission testing. Immunity testing may require a different set of peripherals so you can use software to verify function during tests. I'd suggest a set of USB to Serial RS232 adapters with the serial ports wired for loop-back. Or, simply use well-shielded USB hard drives, and for the test just copy/compare files back and forth in a batch command file; though this method may not be very helpful when sorting out failures, I've used it for years on SCSI devices. Perhaps you may have access to a variety USB peripherals at your employer as I did, which was handy. Otherwise, major name brands with approval marks are recommended. But any combination of approved devices can possibly fail EMC tests in a particular configuration. Good luck! Best Regards, Eric Lifsey At 11:33 AM +0800 11/22/04, <[email protected]> wrote: >? >Dear all, >I have a product (USB Hub) that need to perform EMC testing (IT products). >It's function is to give an extension of 1 to 4 USB port (similar to >electrical extension leads) > >I would like to know how you guys would configuration the product fro testing. > >At the moment I would connect a usb cable (without loading) to one >of the USB ports. > >As if you connect any USB device (i.e. U-disk, mp3 player), the >emissions may come from the USB device instead of the EUT. > >Your comment are appreciated!!!! > >Steven > > >---------------------------------------------------------------- >This message is from the IEEE Product Safety Engineering Society >emc-pstc discussion list. Website: http://www.ieee-pses.org/ > >To post a message to the list, send your e-mail to [email protected] > >Instructions: http://listserv.ieee.org/listserv/request/user-guide.html > >List rules: http://www.ieee-pses.org/listrules.html > >For help, send mail to the list administrators: > >Ron Pickard: [email protected] Scott Douglas [email protected] > >For policy questions, send mail to: > >Richard Nute: [email protected] Jim Bacher: [email protected] > >All emc-pstc postings are archived and searchable on the web at: > >http://www.ieeecommunities.org/emc-pstc This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: [email protected] Scott Douglas [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
