Some one was asking what is the voltage this tiem works. It is DC 19 Volts. Please make sure the polarity. The negative of ground is the inside point on this jack and the outside one is the positive. Hooking up is simple connect the long wire with the stereo jack to an audio source. Tune the ear phones so that you get a reasonably good audio. Then fine tune the Base unit so that the audio is really sharp. Use the ciled wire to charge the Nickel Cadmium batteries inside. Please note connect this hjack only when you are not using the unit for your listening purpose. Take care to switch off the Earphone unit before connecting the charging jack.