This test measures fiber pushback, defined as permanent or semipermanent fiber motion under load. It does not include temporary fiber movement relative to the ferrule due to temperature variations, or permanent fiber withdrawal that occurs when no load is present. The test applies to any type of optical connector in which a fiber is affixed into a ferrule by means of an adhesive.

This test is limited to cylindrical radiused ferrules with non-angled endfaces.

To perform this test procedure, the user must have the capability of measuring the fiber position relative to the ferrule to within the accuracy required by the Detail Specification. Contacting or non-contacting interferometers are the typical types of measurement equipment used.