I used RS39, on my first attempt, and that gave me the 1553B decoder and Power Analysis options, and I already had everything else from the previous time I used the FAB9 option code.
What exactly is the difference between xAxx and xSxx? Do other characters work in the second position?
Nice one
Using S turns on the top bit, whereas A turns off all of the bits.
The top bit is described as the 'License re-application bit' in this text file:
http://gotroot.ca/rigol/DS4000%20Series%20Options.txt
My guess on the A vs S is that its not a licence re-application bit at all. Instead it just changes the option bits to select the PA and 1553B options instead of the standard set of options.
By my calculations there are only 1024 valid option codes:
The first bit in the first position can only be a 0, because 1 equals trial, so that eliminates S through 9. That yields 16 combinations.
The second position can purportedly only be an A or S, so that's 2 combinations.
The third position can be any alphanumeric character combination, so that's 32 combinations.
The fourth position is always a 9 assuming that you want all decoders, so that's 1 combinations.
Thus 16 x 2 x 32 x 1 = 1024
I wonder what would happen if you used the code R999, that would set the bits to 01111-11111-11111-11111.
Edit: Actually I'd like to know what happens for all of the following codes, remember that 0, 1, and I are missing from the code table:
0000
0A00
0S00
1111
1A11
1S11
4000
9999
9A99
9S99
IIII
IAII
ISII
R999
RA00
RA11
RA30
RA31
RA39
RA3I
RA99
RAII
RI00
RI40
RI99
RS39
RS99