From: loki@nazgul.physics.mcgill.ca (Loki Jorgenson)
Newsgroups: comp.sys.sgi
Subject: Re: Mouse for Indigo
Date: 4 Oct 92 04:30:22 GMT
Organization: Centre for the Physics of Materials

In article <1992Sep30.135355.979@alf.uib.no> thune@cmi.no (Nils Thune) writes:
>
>-- 
>Is it possible to get a trackball or a different kind of mouse for the Indigo than the one which comes with the system ?
>
  From discussions about mice last year (prehaps if anyone has something
  new to add they could forward it to me):

	SUMMARY: "Are there alternatives to SGI's mouse for the Indigo?"

	Two replies provided the following solutions; thanks to 
		dtr@durer.ppco.com (Doug Rosenoff)
		erik@westworld.esd.sgi.com (Erik Fortune)

(Note: Replies have been editted)

------ Third party source ------

There is at least one company making trackballs for the Indigo:

According to Doug who spoke to SGI -

Yvonne Mokofsky:
ITAC Systems Inc.
3121 Benton Street 
Garland, Texas, USA  75042
1-800-533-4822  
(214)494-3073

They make a trackball (two grades - user and industrial) which they say
is for SGIs.  If I remember right, the user model runs about US$80 and
the industrial grade model runs about twice that.

They do not send out demonstrators.

------ Homemade solution ------

Hack an existing PC mouse to work on an Indigo.  For example, the
"ballpoint" four-button trackball (driver provided with IRIXv4.0.4):

According to Erik of SGI -

The ballpoint is a 4-button small trackball which I've been using for
months now.  I love it.  By default, the driver provides three buttons
and a lock, but it's configurable.

The ballpoint is a widely-available (in Northern California, at least)
PC serial mouse (make sure you get the serial version).  It runs about
$125US or so.

The cabling isn't really *that* tricky.  "man keyboard" will get you
the pinouts for the mouse port on the keyboard -- note that you only
have MTXD (mouse transmit), so you can't configure the mouse -- you
get default mode only.   If you plug it into a standard serial port,
you have no such limitation.   I'm sure there's ample coverage of 
standard IBM/PC serial pinouts in the world somewhere.  We used the
hardware documentation from a mouse systems mouse (I no longer have
any idea where the documentation is, though).

The hard part is getting enough power to the mouse.   Most PC mice want
approx +/-10 on a bunch of pins.  Each species of SGI machine provides
different power lines and voltages.  Most amusing is Indigo which
provides +8 and -5 which is enough to wake up about 50% of PC mice.
The ballpoint mouse is not one of those.   To finesse the issue, we
just bought a US$7.99 transformer and hooked it directly to the
appropriate pins in the connector.  The resulting cable isn't very
aesthetic but it gets the job done.  We're feeding it +9/-9V which
works, but it sometimes takes a few tries to get it restarted once you
unplug it.

If you have IRIX 4.0.4, you already have the driver for the ballpoint.
Look in:
 /usr/people/4Dgifts/examples/devices/input/io/msballpt.c
					    sys/msballpt.h

---
'gards,                         _        _
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