Numonics 2210 digitizer settings

[per]

I'm putting this out here just in case. Getting technical information on these old digitizers seems to be quite hard as these were never plentiful in the consumer market.

In any way, lately I have been working on figuring out the settings to a digitizer board I have of the type Numonics 2210 (submodel 0-30-C). This one has 8 DIP switches, where only 4 of them are defined by a sticker on the back of the unit, but no mention of the remaining 4 switches. By running the firmware ROM through Ghidra a little, I was able to figure out what the remaining switches do:

Specs:

        30cm x 30cm
        5 mil resolution
        7 bits per byte RS-232
        Firmware C-250-2

Settings:

        Labeled jumpers for RTS/CTS, T and DCE/DTE config inside

        12345678   DIP switches
        ||||||||
        |||||||+-- Operation:
        |||||||      Off = Normal
        |||||||      On  = Test
        |||||||
        ||||||+--- Stop-bits:
        ||||||       Off = 2 bits
        ||||||       On  = 1 bit
        ||||||
        ||||++---- Parity:
        ||||         Off Off = Even
        ||||         Off On  = Odd
        ||||         On  -   = None
        ||||
        ++++------ Baud rate:
                     Off Off Off Off = 19200
                     Off Off Off On  =  9600
                     Off Off On  Off =  7200
                     Off Off On  On  =  4800
                     Off On  Off Off =  3600
                     Off On  Off On  =  2400
                     Off On  On  Off =  2000
                     Off On  On  On  =  1800
                     On  Off Off Off =  1200
                     On  Off Off On  =   600
                     On  Off On  Off =   300
                     On  Off On  On  =   150
                     On  On  Off Off =   134.5
                     On  On  Off On  =   110
                     On  On  On  Off =    75
                     On  On  On  On  =    50

        Test commands:

                C               = Check   Print all checksums
                R               = Read    Prints entire RAM
                W[addr][bytes]/ = Write   Copy data array into RAM
                G[page]:[byte]  = Goto    Call subroutine
                T[]             = Test    Continously print coarse and fine coordinate measurements
                S               = State   Print Cursor/Pen state
                B               = Beep    Sound beeper
                F               = Fill    Set entire ram to FF

                Checksums for Firmware C-250-2:

                        20 CA E6 FA DD E9 FA BD
                        F0 77 A0 25 3A 35 1B BE

Otherwise, it seems like many of these boards from the late 80s at least use the same format for the data-protocol itself: One byte with bit 6 set and button-information in the remaining bits, then a X-Y pair of each two bytes with bit 6 cleared and half the bits of a 10-bit absolute position. I hope this can come of good use to anyone who may need it.

The most interesting thing here is the test-mode. Not too much you can do in terms of running your own programs since the 8039 can't execute from RAM, but you can use it for debugging. The firmware contains a lot of unused subroutines that would be accessible with the Goto-command.