In one embodiment, a docking station on which a data processing terminal is to be mounted has a power source device and a processor. The power source device applies an operating voltage of the data processing terminal and a testing voltage lower than the operating voltage to a power feeding terminal which is in contact with a power source terminal of the data processing terminal. The processor, when having determined that the mounting mechanism is locked, controls the power source device, so that the testing voltage is applied to the power feeding terminal. Further, the processor, when having determined that the mounting mechanism is locked and having determined that the data processing terminal is mounted on the mounting mechanism, controls the power source device, so that the operating voltage is applied to the power feeding terminal.