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Conference noted::ibmpc-95

Title:IBM PCs, clones, DOS, etc.
Notice:Intro in 1-11, Windows stuff in NOTED::MSWINDOWS please
Moderator:TARKIN::LINND
Created:Tue Jan 03 1995
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:3023
Total number of notes:28404

2967.0. "keeping serial mouse active?" by OGBON::GORDON () Fri Mar 28 1997 02:44

G'day

I'm looking for some ideas on hardware issue.

I have 3 p.c.'s all in close proximity. Ideally the preference is to only 
have one keyboard/screen/mouse for all 3. To this end a switch box is to be 
used to link the systems. In testing to-date the switch box functions (not 
completely tested as 2 of the machine have p/s 2 style mouse ports and the 
other has a serial interface, I'm sure that will cause more headaches - 
testing so far is on the serial mouse).

The problem is that when you turn from one system and turn back the 
mouse is no longer active, the video is fine and the keyboard seems more 
than happy. My aim is to keep the multiple systems running simultaneously.

Any ideas how i can keep the mouse active?

Thanks


Des
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2967.1Reboot the mouse?skylab.zko.dec.com::FISHERGravity: Not just a good idea. It's the law!Fri Mar 28 1997 15:2818
Here is an idea:

At least the mice I am familiar with (not PC ones) have different modes that
the s/w can set them to.  The problem with the latter comes when you switch
from one PC to another the first PC has changed modes on the mouse and the
second one doees not know it.

Another possible problem is that the power to the mouse is interrupted briefly
during the switch, but not enough for it to go through a power-up sequence.

The fix is the same for both problems:  Somehow make the switch more slowly so
that power to the mouse is interrupted when you switch and in effect it
"reboots" and sends a power-up message to its new host so the new host knows to
reset its mode.  I don't know exactly how to do this, but if you had a
5-position switch you could put your machines on 1-3-5 and leave 2 and 4 blank
so that switching between them you would have a power-off position.

Burns
2967.2Mouse Power in Switchbox?BOOKS::RAPHAELSONFri Mar 28 1997 15:413
    Maybe you could try having the power for the mouse be applied at the
    switchbox rather than the PC. Then it could stay constant across all
    switch positions, as you'd only be switching data.........Jon.........
2967.3tried some of itOGBON::60709::gordonDes Gordon@snoMon Mar 31 1997 22:4711
g'day

Thanks for the comments so far

re .1: some testing i have done involved disconnecting the mouse 
completely and then reconnecting, the mouse did not work doing this

re .2: I believe that some consoles do this type of thing amd have 
electonics to back it up, these cost heaps unfortunately, it does 
make me wonder  if i could tie some pins together across all ports 
and connect them to the mouse
2967.4WRKSYS::INGRAHAMAndyWed Apr 02 1997 11:337
Switching them might also be interpreted by BOTH ends as a bunch of
random bits, which could throw either the mouse or the driver or both
into never-never land.

Aren't there commercial products for sharing a mouse, keyboard, and/or
monitor between several PCs?  (I think I've seen them advertised in
the back pages of PC Magazine.)  I wonder how they do it?
2967.5PCBUOA::BAYJJim, PortablesWed Apr 02 1997 16:5418
    There should be.  Several laptops (including some older Digital ones)
    incorporate the ability to support the internal pointing device and an
    external mouse at the same time (I'm tempted to say you can hot plug
    the mouse, but I'm not quite as sure about that).
    
    I think its a pity that manufacturers of keyboards with embedded
    trackballs and touchpads didn't have the sense to add a port for a
    regular external mouse, so that you could get the best of both worlds
    from the same device (e.g., I love the touchpad, my wife hates it).
    
    But I know its possible.  Since the mouse gets its power from the host,
    part of the problem is keeping power to it.  The other part, is that
    the mouse holds a dialog with the system when it wakes up (at least as
    part of the boot).  Not sure how to maintain state from that
    conversation, but it can be done.
    
    jeb
    
2967.6ABout $39JULIET::HARRIS_MANetworks Sales ExecWed Apr 02 1997 18:024
    Pickup Computer Shopper and look in the back. Several places sell the
    dual Mouse input to single output devices for $39 or so....
    
    Mark
2967.7maybe not in ozOGBON::60709::gordonDes Gordon@snoThu Apr 03 1997 00:4712
g'day, 

Unfortunately I'm not in the U.S., the prices we have to pay for 
things here are often many magnitudes larger, that is if we can 
get them in the first place and many of the bit's 'n pieces we never 
get.

Thanks



Des