Connector and receptacle containing a physical security feature

In a family of electrical connectors comprising a standard plug and a standard receptacle, a secure connector system for providing discriminating mating among said connectors, said secure connector system comprising:

• at least a first plug and a second plug, said first plug comprising a first primary key in a first primary position and a first secondary slot in a first secondary position, said second plug comprising a second primary key in a second primary position and a second secondary slot in a second secondary position, said first and second plugs differing physically only in the position or at least their primary slot or secondary key, each secure plug differing physically from a standard plug in the existences of both its primary key and secondary slot;
• wherein said first plug is configured to mate with a first receptacle, said first receptacle having a first primary slot in a first primary position and a first secondary key in a first secondary position, said first primary slot adapted to receive said first primary key and said first secondary slot adapted to receive said first secondary key to allow said first plug to mate with said first receptacle to form a mating pair;
• wherein said second plug is configured to mate with a second receptacle, said second receptacle having a second primary slot in a second primary position and a second secondary key in a second secondary position, said second primary slot being adapted to receive said second primary key and said second secondary slot being adapted to receive said second secondary key to allow said second plug to mate with said second receptacle to form a mating pair;
• and
• wherein at least one of said first primary key interferes with said second receptacle or said second secondary key interferes with said first plug to prevent said first plug from mating with said second receptacle;
• wherein at least one of said second primary key interferes with said first receptacle or said first secondary key interferes with said second plug to prevent said second plug from mating with said first receptacle;
• and
• wherein said first and second primary keys interfere with said standard receptacle to prevent said first and second plugs from mating with said standard receptacle.