The keyboard diagnostic consists of an external and an internal loopback. The external loopback requires a passive loopback connector. The internal loopback verifies the keyboard port by transmitting and receiving 128 characters.
The following example shows the keyboard diagnostic output message.
Enter (0-11 tests, 12 -Quit, 13 -Menu) ===> 3 TEST='keyboard_test' SUBTEST='internal_loopback' Enter (0-11 tests, 12 -Quit, 13 -Menu) ===> |