Date: Sat, 31 Dec 2011 00:34:17 +0100 From: "Julian H. Stacey" <jhs@berklix.com> To: Paul Douglas <yachtchal@gmail.com> Cc: freebsd-usb@freebsd.org Subject: Re: cherry keyboard issue Message-ID: <201112302334.pBUNYHkE007353@fire.js.berklix.net> In-Reply-To: Your message "Fri, 30 Dec 2011 14:35:57 GMT." <CAEwx77Okiz_H7vD09qRcjgVy63_ru0ncitDkXYo36%2BtH1WA5wg@mail.gmail.com>
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Paul Douglas wrote: > I recently posted a query on the peripheral hardware forum about a problem It's not always software at fault ... Did you measure the current each keyboard uses ? They do vary a lot. The PS2 mini keyboard I'm using uses 46 mA, other PS2 full sizers on shelf here pull 63 & 70 & 83, another mini PS2 here pulls 88 mA, one PS2 I recall pulled 150 or so & was troublesome on some PCs so I dumped it. Then add whatever a USB to PS2 converter draws. I havent measued what my one USB2 keyboard drawa. Or my USB to PS2 or PS2 to USB converters. I went through various other kit & & wrote cconsumption under devices. USB-2 is spec'd at 0.5 Amp, but I suspect some sockets (on PCs & hubs) dont deliver enough & some devs (disks) obviously draw 0.7+ & need doubler cables. Keyboards shouldnt be near 0.5A but conside dried out electolytic capacitors on USB power supplies etc. Certainly seen that on hubs & transformer (for USB & ethernet) Cheers, Julian -- Julian Stacey, BSD Unix Linux C Sys Eng Consultants Munich http://berklix.com Reply below not above, cumulative like a play script, & indent with "> ". Format: Plain text. Not HTML, multipart/alternative, base64, quoted-printable.
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