Abstract: A data processing device has a battery compartment in which a battery is fastened by a releasible latch. A manually actuated eject button is used to release the battery. A light is source is placed in or near the eject button and provides, when illuminated, a light signal warning the user not to eject the battery. The eject button is covered by a door, and both the door and button are designed for two handed operation which, in addition to preventing accidental actuation of the button, forces the user to concentrate attention on the eject button and warning light.