Calcomp digitizer 33360

[Rolf Krell]

Hello !
I've tried to use a Calcomp digitizer model 33360, 16 button cursor.
I'm using the GRASS Calcomp driver cc95f23_16 .
When running v.digit everything seems to work correctly. Map registration 
points can be exactly registered (key 0-4 are working correct), but then
     - the calculated scale is 1:3 while the original scale is 1:5000 !!!
     - when trying to digitize, I get  "Digitizer read error. Do we continue (y,n)?"

I've also tried the Calcomp diagnostic program "calc_diag"
     - I can hear a beep, but nothing else happens.
Is there a way to connect the digitizer with a GRASS Calcomp driver, what are the 
changes?
I would be grateful for your help
                                   Rolf Krell