[techtalk] Keyboard/Mouse Reset Hardware Problem

Conor Daly conor.daly at oceanfree.net
Sun Nov 12 13:26:42 EST 2000

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

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.

Conor Daly <conor.daly at oceanfree.net>

Domestic Sysadmin :-)

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