Abstract: An apparatus to identify the manufacturer of a battery is provided, the battery typically includes a DC signal pin and a grounding resistor. The apparatus includes a keyboard controller. The keyboard controller includes an analog to digital converter (ADC) with an ADC signal pin. The ADC signal pin is connected to an end of the grounding resistor through the DC signal pin, and the other end of the grounding resistor is grounded. It is of advantage that the DC signal pin of the battery is coupled to the ADC signal pin of the keyboard controller. The voltage of the DC signal pin is converted into a multi-bit digital signal to compare with a list programmed in the keyboard controller, to identify any of a large number of various different battery manufacturers.