Method of and apparatus for selectively controlling a plurality of remotely located loads

DETAILED DESCRIPTION I claim: 1.
A system for operating a plurality of variously remotely located loads from a single master location, said system comprising: a master controller at said master location including means for generating a succession of voltage signals each of positive or negative polarity and of a voltage level either above or below a predetermined threshold; at least four slave units connected in parallel to said master controller and each at and connected to a respective load; means including a conductor extending between said master controller and all of said slave units for feeding said signals to all of said units; priority means in one of said slave units for operating the respective load on reception over said conductor of a signal having either of said polarities; handicap means in another of said slave units for operating the respective load only on reception over said conductor of a signal of at least one of said polarities and having a voltage level above said threshold; negative-responsive means in yet another of said slave units for operating the respective load only on receptin over said conductor of a signal of negative polarity; and positive-responsive means in yet another of said slave units for operating the respective load only on reception over said conductor of a signal of positive polarity.
2.
The system defined in claim 1 wherein said priority determination means includes a bridge circuit connected to said conductor.
3.
The system defined in claim 1 wherein said handicap means includes a zener diode.
4.
The system defined in claim 1, further comprising switch means connected to said handicap means for changing the handicap thereof and operating the respective load on reception over said conductor of a signal having a voltage level below said threshold.
5.
The system defined in claim 4 wherein said handicap means includes a zener diode, said switch means including a normally open switch connected across said zener diode.
6.
The system defined in claim 5 wherein said switch means includes a thyristor connected across said zener diode and means for feeding a voltage pulse from said conductor into the gate of said thyristor, whereby after firing of said thyristor by said pulse a drop to zero potential in said conductor opens said switch means