Standard pci and isa interface for easy access to your desktop pc. 4-digit display. Frontal 2 digit for current error code and back 2 digit for previous error code. Post (power on self test) card displays error code quickly when booting. Error code table offered makes you know the error details easily. Hexadecimal character display. Supports 80h, 84h and 300h port and compatible with all mainstream motherboards. Supports code search function. (While testing, press s1 button 1 second to start up search, press s1 half second to start down search till end, then press s1 1 second again to start down search and press s1 half second to search previous error code till end.) Supports motherboard bus speed test.