Summagraphics tablet?

From: Jules Richardson <julesrichardsonuk_at_yahoo.co.uk>
Date: Wed May 5 09:08:29 2004

On Wed, 2004-05-05 at 07:34, der Mouse wrote:
> I have the thing opened up right now. There are 24 DIP switches, three
> banks of eight, labeled SW1 through SW3.

Yikes! That's a lot of combinations to run through! :-)

I was in the same situation with the old Numonics tablet that I was
given - no documentation anywhere and the standard mode it was
configured for didn't make much sense and wouldn't work with any
drivers. Luckily I only have 8 switches to run through though... I found
something that happened to work with one of the later Numonics drivers.

> There is a good deal of "small" logic, CMOS and TTL in the cases I've
> bothered to look at the numbers on, a bunch of discrete components, and
> three socketed "big chips": a 2732 UVEPROM with a sticker on which is
> handwritten "1103" and "7.9"; a 74C154 (why this is socketed I have no
> idea); and something that looks like a CPU, on which is printed various
> things in various ways; I think it's probably an 8031.

Well I suppose they run as a SBC, taking input from the pad and
converting to the necessary protocol before spitting it down the serial
line.

> There's also a momentary pushbutton switch of no obvious function
> (inaccessible with the cover on) labeled SW4

reset, to allow an engineer to reset the pad without killing the power
all the time? My Numonics tablet has a reset on the back - I'm not sure
why the user would ever need to do a reset though.

> and a six-contact card-edge connector of equally obscure function.

My tablet's got both a pen and a puck; maybe that's a pen connector?

cheers

Jules
Received on Wed May 05 2004 - 09:08:29 BST