VDC would be the abbreviation for Volt Direct Current which translated would volts direct current. The idea of ??this type is unidirectional current to the load. Direct current is normally produced by batteries, thermocouples, solar cells and a dynamo electric machine type. The direct current can flow in conductors such as wires, but may also flow through semiconductors, insulators ... In the image: 1 - current per pulse 2 - Direct Current (DC) 3 - Alternating Current (AC) 4 - Variable Current

IEEE 1394 (also known as FireWire by Apple Inc. and as i.Link by Sony) is a type of connection for various platforms, for the input and output serial data at high speed. Typically it used for the interconnection of digital devices such as digital cameras and camcorders to computers. There are four versions 4, 6, 9 pin.