Abstract: A system for testing an electronic device comprises a first output, a second output, and a third output connected to a positive input, an identification input, and a negative input of the electronic device, respectively. The system further comprises a switch comprising at least two dynamic contacts, each of which is connected to a resistor for the use of identification.

Abstract: A system for testing an electronic device comprises a first output, a second output, and a third output connected to a positive input, an identification input, and a negative input of the electronic device, respectively. The system further comprises a switch comprising at least two dynamic contacts, each of which is connected to a resistor for the use of identification.

Abstract: The present invention relates to a hook device which can be firmly positioned on a nailer, wherein a fastener is used to insert in the rear plug by cooperating with a ring-like hook, so as to make the rear plug slightly bulge out to press against the ring-like hook, thus, the ring-like hook is firmly fixed to the rear plug. The hook device can be arbitrarily and rotatably positioned on the nailer, wherein a plurality of positioning grooves are formed on the step circular wall of the rear plug, and a ring-like hook is mounted on the rear plug. The ring-like hook is provided with a positioning unit which is to be engaged in the positioning grooves of the rear plug, so as to enable the ring-like hook to be rotatably positioned on rear plug. Thereby, the user can position the nailer arbitrarily according to real needs.