Abstract: A connection system for providing selective interconnection between a fiber optic connector plug and a receptacle socket. The connection system is configured for implementation in push-pull type connectors having a dual housing structure, including an inner housing and an outer housing. The connection system comprises a connector inner housing and connector outer housing having predefined keying geometries, including protrusions and channels/slots that may be formed onto the outer and inner surfaces of the respective connection devices. The connection system further comprises a receptacle socket, including protrusions and channels that may be formed onto the inner surface of the connection device. The protrusions and channels formed on the connector's inner and outer housing are configured to mate with corresponding keying features found on the receptacle socket, thus allowing properly keyed connection devices to interconnect.