Re: ADB Switchbox requirements

[ToasterKing <toasterking@SPLATbigfoot.com>]

In article <f6ab8a2f.0309141712.29c6b7ea@posting.google.com>, Roughana
<andrew.roughan@writeme.com> wrote:

> I would like to use an ADB Switchbox with my systems so that I only
> need to have one keyboard and mouse on my desk.
> Systems that I want to switch between are Apple IIgs, LC 630,
> Powerbook 1400c.
> 
> Do I need one specially wired switchbox cable or will a standard ADB
> cable work fine?
> Can I switch between systems while the power is on?
> I get the impression that this is not recommended but could work.
> What is the issue and what damage could this cause?
> 
> Thanks,
> Andrew

Wow, are ADB switchboxes actually manufactured and sold?  I just built
an ADB + analog stereo sound A/B switchbox to allow me to share a
single keyboard, mouse, and set of monitor speakers between my IIgs and
Mac.  The keyboard is the AppleDesign [extended] Keyboard, model M2980
and the mouse is a Macally 2-button mouse.  There is only one problem I
have with the ADB switching, which involves my (third-party) Macally
2-button Macintosh mouse.  The problems:
1. The GS doesn't seem to like the sampling rate of the mouse.  When
sliding the mouse slowly, the pointer in GS/OS moves slowly and very
jerkedly.  When sliding the mouse quickly, the pointer in GS/OS does
not move hardly at all, and sometimes even moves the opposite
direction.  I'm not sure if this is an issue with the mouse driver in
GS/OS or the ADB firmware itself.
2. When switching to any other position, then back to the Mac, the
second mouse button fails to work until a restart.  If I open the
"Point Device" control panel supplied with the 2-button mouse, then
both buttons work, but the keyboard ceases to work until I restart the
Mac.  This can be attributed to poorly written 3rd-party mouse
software.

If you're using genuine Apple hardware, you shouldn't have any problem
at all.  The only problem I've ever seen with hot-plugging ADB on a Mac
(certain models) is that the mouse tracking may be sluggish until
restart.  Apple recommends not switching ADB cables while the system is
powered on, but I and many other people have been doing this for years
upon years with no problem.  Apple has to recommend against doing it,
though, since it wasn't particularly designed for hot-swapping.  It
could produce unusual results, or a static discharge could potentially
fry the ADB controller or peripherals.  As long as you have a good
ground though, there shouldn't be a problem.  Again, with genuine Apple
hardware, I've always seen it work.  Heed the advice Bill provided
about the mandatory "dead spot" in the switch, which any
professionally-assembled ADB switch should have.  A standard ADB cable
should work fine.  Hint: If you don't have spares, you can also use an
S-Video cable in place of an ADB cable -- they're identical as far as
connectors and shielding.

Good luck.
TK

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