This photo is an underside view of the upper plate of a functional test fixture (FCT fixture). The plate will move downward to engage the unit under test (UUT). The fixture’s programming pins (center) are floated so they can self-align with the connector on the UUT. Also shown is the test fixture’s array of LED sensors (mounted on the black machined bar). They will also self-align to the UUT and will detect the light that is output from the UUT’s LED array.