This is known as a "kluge" box.  This box is an electric duplicate of the front panel controls of the DDP-124 computer that's used to drive this simulator.  The box allows a tech to change the programming of the system while the computer is running.  Since each lamp and instrument in the cockpit is memory mapped, you can also check the operation of each and every indicator and instrument that's in the cockpit.  This is very handy when trying to solve a wiring short, or to verify the operation of a system that was recently repaired.
 


This is a closeup view of the Kluge box.  I know it looks rough, but keep in mind this thing is 32 years old.
The series of 7 segment displays show the currently selected memory address.  In octal.
 


Here is one portion of the instructor's panel.  From here, the instructor can control all aspects of the flight being simulated.  From engine fires to wind shear, it's all done right here.
 

 Continued...