Abstract: The present invention relates to a method for charging an electrical device (102) with a charger (101) via a data interface (103). The data interface (103) comprises at least a first data line (D+) and a second data line (D?) coupling the charger (101) and the electrical device (102). According to the method, the charger (101) and the electrical device (102) are coupled through the first and second data lines (D+, D?). At the charger (101) the first and second data lines (D+, D?) are short-circuited (301). The electrical device (102) detects, if the first and second data lines (D+, D?) are short-circuited and in response to the detected short-circuit (301) at the charger (101), the electrical device (102) short-circuits (401) the first and second data lines (D+, D?). Then, the charger (101) opens the short-circuit (301) of the first and second data lines (D+, D?) and detects, if the first and second data lines (D+, D?) are short-circuited at the electrical device (102).