Alternate Insert Rotations for Mil-Spec Connectors

Prevent Connector Cross-Mating

Cylindrical connectors are polarized in direct relation to their corresponding mated half for proper contact alignment. Polarization is achieved via a plug’s master key, which matches with a master keyway on the receptacle. Alternate insert rotations or alternate shell keying helps to prevent cross-mating by differentiating between similar looking connectors with the same insert arrangement or shell size so that only matching pairs are able to couple. Alternate rotations and keys are particularly useful in panels with high densities of similar connectors where there is an increased risk of accidental cross-mating.

All Milnec connector series offer alternate rotations or keys as a means of preventing cross-mating. When the insert or key is rotated a set number of degrees, the contacts are unable to align and the connectors are unable to couple, signifying a mismatched connector set to the operator. Alternate insert rotations are specified by the letters N (normal), W, X, Y, and Z. Alternate keys are designated by the letters N (normal, A, B, C, D, and E. Alternate rotations and keys are established during manufacturing and are not user configurable.

Alternate Insert Rotation Examples

Normal RotationW RotationX RotationY RotationZ Rotation
* Rotation angles for illustrative purposes only. Actual Rotation angles vary by insert.