A test mode is a mode, usually hidden, inserted into consumer electronics by the manufacturers. They are generally only intended to be used by authorized maintenance workers, but are sometimes unintentionally discovered by a customer. Test modes usually include functions such as displaying test card images and testing moving parts.
Test modes in handheld gaming consoles
Test modes are also inserted into consumer handhelds and are often found as a hidden access mode in electronic gaming consoles. Its main focus is to test the functions and sound files to confirm that all the sounds are present and the speaker is working. Accessing the test mode on an electronic handheld game console usually involves pressing a combination of buttons and inserting a battery or holding the reset button, but this isn't always the case.