What are the jumpers used for on the c-10 breakout board

The USB is only used for powering the parallel breakout board.

Additional Solution:

there are 2 sets of jumpers, one set is to set the com or common to ground or 5v. if you set it to 1-2 then comm is equal to ground. 2-3 equal to plus 5v. You can locate the comm terminals between pins 2-9. Then there is another jumper to set pins 2-9 to input or output if you set it between 1-2 it is output. If you set it between 2-3 it is input.

Additional Solution:

endmill-singleflute endmill-twoflute endmill-compression carveandengrave endmill-surfacing