A method and apparatus for coating a plurality of semiconductor devices that is particularly adapted to coating LEDs with a coating material containing conversion particles. The charging units come in a variety of sizes as well as in multiples of each size. When the device can automatically answer the incoming call, advanced features such as Push To Talk, Information Tone, Click to Call, and Remote Monitoring may be easily implemented. The pair of the power supply wires and the pair of the signal wires are respectively disposed diagonally.