US Patent 7859286 Electronic device test system

When the number of DUTs carried on a loader buffer and scheduled to be held by contact arms at the next test is less than N, a DUT at a contact arm corresponding to a missing position at the loader buffer among the N number of DUTs being held for execution of a current test is held as it is without being ejected. While holding this DUT, the DUTs carried at the loader buffer for execution of the next test are picked up and the test is executed in that state.