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Control panel has row of 15 "ternary" red-green indicators:

    * Lights 1,2,3,4,5,6,7,8,9 - value of PC register (address of current operation)
    * Lights 10,11,12 - 3-trit data (see below)
    * Lights 13,14,15 - current value of A register

Also control panel has row of 15 "ternary" slide switches:

    * Switches 1,2,3,4,5,6,7,8,9 - some 9-trit address entered by user
    * Switches 10,11,12 - some 3-trit data entered by user
    * Switch 13 - control input/output ternary switch:
       - P (top position) - using specified address write data to the memory (data
            lights display this 3-trit data)
       - O (neutral position) - ignore address and data switches (data lights
            display data from memory address PC)
       - N (bottom position) - ignore data switches and display data from
            specified address
    * Switch 14 - control subprogram ternary switch:
       - P (top position) - interrupt main program, save current PC and jump to
            specified address
       - O (neutral position) - do not disturb working program
       - N (bottom position) - stop subprogram and restore PC to return to
            main program
    * Switch 15 - control step/run ternary switch:
       - P (top position) - execute one step of the program
       - O (neutral position) - pause mode
       - N (bottom position) - run program from current position