On Mon, 18 Dec 2006, Ethan Romander wrote: > On Tue, 2006-12-12 at 16:31 -0500, Alan Stern wrote: > > -snip- > > > They seem to occur every 5 or 10 seconds, roughly. The most likely cause > > is a bad USB cable connection. You might want to check the cable, or > > even check if there's a cable inside the computer case running from the > > USB port to the motherboard. Try also connecting the keyboard to > > different USB ports on the computer. > > It looks like switching to another USB port on my machine fixed the > problem. It has been several days now, and I haven't experienced any > trouble with the keyboard at all. Now why didn't I think of trying a > different USB port earlier? Probably because I was searching for _some_ > use for those old USB 1.0 ports on the machine. Maybe I'll get one of > those USB foot warmers, or maybe some USB LED indicators.
For all we know, the problem could have been caused by a poor electrical contact between the cable and the USB port you were using. > This brings up another topic: What makes a good USB cable? I pick up > USB cables from the local computer surplus store for a couple of bucks > each (living in California's Silicon Valley is great for cheap computer > parts). The cables certainly seem to be the same quality as those > costing several times more. I've never had any problems, but I hear > lots of chatter about "bad" or "cheap" USB cables causing problems. Are > bad cables really all that common? What makes a good cable? How about > USB "extension" cables? Are they permitted under the official USB spec? > Do they often cause problems? These questions aren't easy to answer. One wants to have good electrical contacts at the terminals and good electromagnetic shielding. But with low-speed devices like keyboards and mice the shielding is not so critical (which is good since people wouldn't like having their mouse attached to a cable made stiff by all that shielding). There are technical specs on cable characteristics in the official USB documents, but they aren't likely to be much help to consumers. I believe the spec does rule out "extender" cables, but of course they often work well nevertheless. In practice, about all I can say is that some combinations of cables and equipment give rise to problems. A number of people have run into these sorts of problems, but it's impossible to say what percentage of all users are affected. And to make things worse, I'm sure that sometimes the actual problem lies in the electrical contacts or components built into the port or device connector, not in the cable itself. > Thanks for all your help troubleshooting this, Alan. You're welcome. Happy holidays. Alan Stern ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Linux-usb-users@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-users
