1)The original A-B switch box, with 3
DB-25 connectors.

2)Mark the hole centers for the mounting holes

3)Spot punch the hole centers

4)Drill out the holes with a 1/8 in drill.

5)Remove the box cover with a Phillips
screwdriver.

Remove the A and B connectors and the
rotary switch. Cut the I/O port wires near
the switch end.

6)Mount the controller board to the bottom
of the box with standoffs.

7)Wire the I/O port to the controller board.  Temporarily removing the I/O connector
will aid in wiring the controller board. 
If desired, attach limits e-stop and other
connections directly to the DeskCNC
controller board. If the existing driver box
has these connections, connect the
corresponding pins in the DB-25 connector. 

These connections will vary with different
parallel port controller setups.

8)Side view of the wired connections.  Attach power supply to the conroller terminals in the foreground.

9) Put the lid back on the box.  In above
picture B is the serial port connector and at
A the board power LED can be seen.

Finished box with serial and parallel
cables attached