Connector system having keyed mating

A receptacle cage comprising:

• shielding walls forming a module channel configured to receive a pluggable module, the shielding walls including a first end wall, a first side wall extending from the first end wall and a second side wall extending from the first end wall opposite the first side wall, wherein the first end wall, the first side wall and the second side wall form the module channel;
• a hood extending from the first end wall forming a chamber located radially outside of the module channel with the first end wall separating the module channel from the chamber such that the first end wall is located between the module channel and the chamber;
• an EMI gasket coupled to the hood and the first end wall, the EMI gasket having a plurality of deflectable spring fingers, the deflectable spring fingers including inner spring fingers extending along the first end wall inside the module channel to interface with the pluggable module, the inner spring fingers separated by inner gaps;
• and
• a cage polarization feature for keyed mating of the pluggable module in the module channel, the cage polarization feature including at least one cage polarization slot formed in the first end wall being open to the chamber, each cage polarization slot being aligned with the corresponding inner gap of the EMI gasket between the inner spring fingers, each cage polarization slot configured to receive a corresponding module polarization feature of the pluggable module.

A set of receptacle cages comprising:

• a plurality of receptacle cages including a first receptacle cage and a second receptacle cage, each receptacle cage of the plurality of receptacle cages comprising:
• shielding walls forming a module channel configured to receive a pluggable module, the shielding walls including a first end wall, a first side wall extending from the first end wall and a second side wall extending from the first end wall opposite the first side wall, wherein the first end wall, the first side wall and the second side wall form the module channel;
• a hood extending from the first end wall forming a chamber located radially outside of the module channel with the first end wall separating the module channel from the chamber such that the first end wall is located between the module channel and the chamber;
• and
• a cage polarization slot formed in the first end wall, the cage polarization slot open to the chamber, the cage polarization slot configured to receive a module polarization feature of the pluggable module such that the module polarization feature is located in the chamber and covered by the hood;
• wherein the cage polarization slot of the first receptacle cage is located a first distance from the first side wall of the first receptacle cage and the cage polarization slot of the second receptacle cage is located a second distance from the first side wall of the second receptacle cage, the second distance different than the first distance such that the pluggable module pluggable into the module channel of the first receptacle cage is unable to plug into the module channel of the second receptacle cage.