[techtalk] Keyboard/Mouse Reset Hardware Problem

ktb x.y.f at home.com
Sun Nov 12 10:34:54 EST 2000

Conor Daly wrote:
> Any i386 hardware gurus out there?
> I've got a 4-port (Hardware only) Data switch for monitor, keyboard and
> mouse that I'm using to share monitor etc between three Intel / AMD
> machines running a mixture of M$ Windows, BeOS and RH6.2.  Both keyboard
> and mouse are PS/2 but the keyboard connection to one machine goes through
> an adapter to an AT keyboard socket.  Issues arise when switching between
> machines.  The Monitor works fine in all cases.
> 1). Windows/RH6.2/BeOS on AMD K6-2 350, 64Mb ATX MOBO PS/2 keyboard and mouse
> ports:
> If I switch to the Windows machine, most times the keyboard won't work
> until I physically disconnect and reconnect it from the Data Switch.  This
> seems to provoke a Keyboard Reset and all is fine.  Sometimes the mouse
> fails to work.  I thought of a Keyboard reset switch which would
> disconnect one or more wires to the keyboard and would provoke a reset
> when reconnected.  Quite easy to do but may not work with No.2 below.  For
> the mouse, I presume it's something like Windows not noticing the mouse on
> the port and assuming it's gone and not trying again (It must see the PS/2
> mouse at boot time or it won't load its driver).  I thought of leaving one
> crucial wire connected to all machines so that they all see the mouse as
> alive if I knew which wire/pin I should use.
> 2). RH6.2 Network server on Intel P200MMX, 32Mb AT MOBO ps/2 mouse port, AT
> Keyboard port using AT-PS/2 adapter.
> When switching to this machine, sometimes the keyboard will reset and
> sometimes not.  If it doesn't reset, I can reset it by disconnecting as in
> No.1 above but that doesn't always work.  Lately, the keyboard doesn't
> seem to work at all.  I'm kinda thinking there's some issue with the AT
> keyboard port as opposed to the PS/2 port.  Could there be something more
> involved with an AT keyboard?  Does the OS notice any difference (since a
> PS/2-AT adapter seems to work nicely).  Again, would a reset switch work?
> The mouse doesn't work until I do a '/etc/rc.d/init.d/gpm restart' as root
> (I could probably sudo that or something).
> 3). RH6.2 Internat Firewall/Router on Intel 486DX66, 16Mb Proprietry MOBO
> with PS/2 mouse and Keyboard ports.
> Switching to this machine is easier (and less frequent) than for the
> others.  The keyboard works on a disconnect/connect cycle every time and
> the mouse works with the same as for No.2.
> So, My problem is:
> a). Will the use of a Keyboard Reset switch solve the keyboard problem and
> if so, do I need to disconnect all pins or just one (which pin?)?
> b). What's different with the machine using the PS/2-AT keyboard adapter?
> Can I do anything about that (remember, when I switch to this machine I
> have neither keyboard or mouse input available)?
> c). Is there a pin on the mouse port that, when permanently connected to
> the mouse, will convince the PC/OS that the PS/2 mouse is still connected?
> I could then hardwire all of those pins together on the data switch.  Will
> this break stuff (eg. MOBO, Mouse etc)?
> d). How long can a PS/2 or VGA cable be?  I want to relocate the server and
> router in the attic and it would be nice to be able to physically connect
> to them from my usual workstation using the data switch.

I can't answer all your specific questions but I can share my
experience with these types of switches.  First off I know you can
purchase 30 foor ps/2 cables.  I don't know if that is a max but
that is the longest I've seen sold so far.  

OK the switch.  I purchased one of those 4 port hardware switches
and it just simply doesn't work for my purposes.  I tried two
different ones.  The mouse kept getting lost.  There were ghost
images all over the screen.  It worked better with my Windows box
than it did with my Linux box.  I have a Belkin 2 port (omnicube)
KVM switch at work that works perfectly but it is a little pricey 
If you have the bucks spring for one of those.  I ended up getting
an Aten (MiniView).  It works ok except my scroll mouse doesn't work
even though the docs say it is supported.  It is a used unit so
maybe it has something to do with that.  I don't know.  My
suggestion to you is, save yourself the time and effort and get a
different switch.  
"Neurosis is the way of avoiding non-being by avoiding being." 
- Paul Tillich, American theologian (1886-1965).

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