Date: Sun, 15 May 2011 22:02:54 -0700 From: perryh@pluto.rain.com To: freebsd-questions@freebsd.org Subject: Re: No keyboard after ports update, 2x moused_enable="YES" culprit Message-ID: <4dd0affe.XOOWAi%2BbOV2dBAI6%perryh@pluto.rain.com> In-Reply-To: <A7E3D778F97B0551A7DFB430@mac-pro.magehandbook.com> References: <117637.44743.qm@web111903.mail.gq1.yahoo.com> <20110515103646.7558ddb2.freebsd@edvax.de> <4dd09401.Qf5DE46mpnXg4G2w%perryh@pluto.rain.com> <A7E3D778F97B0551A7DFB430@mac-pro.magehandbook.com>
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Daniel Staal <DStaal@usa.net> wrote: > --As of May 15, 2011 8:03:29 PM -0700, perryh@pluto.rain.com is > alleged to have said: > > > The AT and PS/2 keyboard interfaces are electrically identical > > -- only the physical connector is different. > > --As for the rest, it is mine. > > The physical connector is all that actually needs to be different: > Hot-swap interfaces make a point of connecting ground before power, > usually be longer ground pins. The PS/2 should qualify on this point, provided it is wired _correctly_ (with the connector shell grounded both on the motherboard and in the cable). I'm less sure about the AT, which used a 5-pin DIN plug that may not even have had a shell-ground on the motherboard -- we were less concerned about generating RFI in those days. IIRC all 5 pins were the same length. It's possible this particular Belkin keyboard used longer pins for power and ground than for signal, so as to be safely hot-pluggable even if the motherboard didn't ground the connector shell. However, I've since gotten by with hot-plugging a PS/2 trackball on the same machine a couple of times, to clear lockups.
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