Keying for connector systems

Keying may be used to indicate various features of cables, cable connectors, and/or equipment. The keying mechanisms of the connectors systems disclosed herein identifies whether each plug is a pinned plug or a pinless plug. The keying mechanisms disclosed herein identify the number of optical fibers terminated at each plug. For example, one type of keying mechanism may indicate a cable plug manufactured under a 40 Gb/sec standard and another type of keying mechanism may indicate a cable plug manufactured under a 100 Gb/sec standard. The keying mechanisms may indicate a cabling/wiring pattern to be used (e.g., indicates a polarity of the cable). The cables and/or plugs may be color coded based on the keying mechanism. Accordingly, the keying may alert a user to the features of the cable that are not readily apparent upon a cursory inspection.