Summagraphics tablet?

From: der Mouse <mouse_at_Rodents.Montreal.QC.CA>
Date: Tue May 4 03:51:16 2004

Does anyone know, or know of a reference to, the serial-line protocol
spoken by Summagraphics tablet digitizers (specifically, the MM1103)?

I have one. After a bit of detective work, I got it to at least
somewhat work. I now have it to the point where I can connect it up
and turn it on. When I do, I get nothing until one of the buttons on
the puck is pressed, at which point it starts generating a stream of
samples, continuing for as long as some button is pressed. The format
is fairly easy, just %04d,%04d,%1d\n sent with the 0x80 bits set to
provide even parity, where the four-digit numbers are the location
(based on an 8.5" edge of a piece of paper and some arithmetic, it
appears to be 200dpi) and the last indicates what button is pressed.

This makes it all at least somewhat usable. But I'd really like to be
able to get samples back even when no buttons are pressed, whence my
question.

The back does include a sticker saying, among other things, "BIT PAD
FORMAT", which may or may not mean anything useful. I did go
a-googling, but either there's nothing to be found or I didn't guess
the right incantation to find it. `Summagraphics MM1103 serial
protocol' turns up no hits - though it probably will once this message
gets archived and googled :) - and neither did `"bit pad format"'.

It _is_ on-topic; there's a sticker on the back with a Date: field
containing a handwritten date that is clearly in 1984 (it appears to
read "10/17/84"), which contains other text implying it was added by a
leasing/service organization.

Thoughts?

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Received on Tue May 04 2004 - 03:51:16 BST