Within a FireWire cable are two power connections, which can be used to transfer between 8 and 40 volts at up to 1.5 amps to IEEE 1394 peripherals on the chain. This power is used to maintain a device’s physical layer continuity when devices are powered down or malfunctioning, as well as to provide power to devices on the bus. Also within the cable are two twisted pairs for data signaling. These signal pairs are individually shielded, and the outside of the entire cable is also protected by shielding. The connectors on the ends of 1394 cables have their origins in the Nintendo GameBoy connector. These connectors are both flexible and durable. The electrical contacts are constructed inside the structure of the connectors so that contamination and shock are prevented.