The Atmel AVR ONE! is shipped with a self-test adapter with an IDC cable. If it for any reason is suspected that the AVR ONE! cable and probe are not functioning correctly, a self-test can be run. The self-test adapter is a loopback adapter that enables the on-board MCU to perform diagnostics on the target communication circuitry. This includes the probe, the cable, parts of the main board, and implicitly the test adapter itself.