Calcomp 9500

[Mixon, Marlin]

...Aldo Clerici was having trouble connecting a Calcomp 9500 to a Linux 
PC 
running Grass...

I don't know much about the Grass end of things, but I know Linux.  
Nowhere in your description did you mention what serial port you were 
connecting your
digitizer to.

Just as MS-DOS has com1: com2: com3: and com4:, Linux has /dev/ttyS0,
/dev/ttyS1, /dev/ttyS2 and /dev/ttyS3.  I would assume that you would
somewhere have to tell Grass which port you were using. 
--Marlin Mixon