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| Thread ID: 46053 | 2004-06-11 23:48:00 | How do OSs know the difference between USB1 & 2? | riscpc (5756) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 243605 | 2004-06-13 03:08:00 | This is a bit strange. Linux doesn't know about USB devices it doesn't know about. :D Unless it has a table entry matching a driver module to the VendorID/ProductID numbers programmed into the device and sent to the overall USB driver in the recognition protocol, it can't use it. The best way to see what is happening is to plug a USB device in, then do tail -20 /var/log/messages. (You'll probably need to be root to see the messages file). Does W98 have USB2? :D Windows XP "complains bitterly". :O Perhaps it is cable after all. " ... two sets of wires..." means two sets of four wires? (External USB cables use a twisted pair for the data, and a pair of heavier [not necesarily twisted] wires for power. The shield goes over all, I think. I suppose internal ones are so short they don't need shielding on the data wires for USB 1.1 . The rear ones have shielded cables. ;-) So maybe the data cables have to be shielded twisted pair for USB2.. Ribbon cable is cheap to assemble to IDP connectors, so the front cables are ribbon? |
Graham L (2) | ||
| 243606 | 2004-06-13 08:02:00 | Interesting subject, I recently had a tower case in for repair with what I think is a interference suppressor in the form of a round magnetic wrapped around the front USB cables between the plugs and the board. The reason I think it is for noise suppressing is I have fitted the same type of magnetic on RS232 data cables for magnetic card readers to stop interference on the communication cable which is connected to the host PC. Has anyone seen this setup on front USB port cables. John. |
john r (782) | ||
| 243607 | 2004-06-14 03:16:00 | Usually those ferrite anti-interference blocks are put on external cables to reduce the radiation from the computer box, rather than to stop noise getting in. EMC standards. :D They shouldn't affect the signals in the USB cable ... the data signal is differential, in a twisted pair. The ferrites absorb common-mode noise. |
Graham L (2) | ||
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