Once the system is enabled, the operator can select with a $3$ position selector $$SW$1$ between three $(3)$ different logical functions, OR$,$ AND and EXOR. After the function is selected, there are $2$ N$.$O$.$ Pushbuttons that the operator can press as inputs to the logical function. An indicating light $($LT$0$ in Output $0)$ turns ON depending of the selector switch position and the status of the momentary Pushbuttons. In another words, the position of the selector switch $$SW$1$ decides which following logical function will be performed: Position $1($Input $1)=$ The system performs a logical OR Position $2($Input $2)=$ The system performs a logical AND Position $3($Input $3)=$ The system performs a logical EXOR PB$-$A $($Input $5)$ and PB$-$B $($Input $6)$ are two inputs for the logical function selected. Description of System number $2($using the same Inputs of the System $1$ above$)$ There are $3$ lights connected to Output $1,2$ and $3.$ The lights turn ON as follows: $-$ LT$1($output $1)$: If the SW$1$ is in position $1$ and the PBA is pressed. $-$ LT$2($output $2)$: If the SW$1$ is in position $2$ and PB$-$A or PB$-$B are pressed. $-$ LT$3($output $3)$: If the SW$1$ is in position $3$ and both PB$-$A and PB$-$B are pressed.