FireWire 400 and 800 Cables and Connectors

FireWire 400 and 800 Cables and Connectors

System Dependencies
Minimum PowerSDR Version:
Applicable Hardware: Any FireWire enabled device

Content provided by: FlexRadio Systems Engineering

FireWire 400 (IEEE 1394a)
Cable length is limited to 4.5 meters (14.8 ft), although up to 16 cables can be daisy chained using active repeaters, external hubs, or internal hubs often present in FireWire equipment. The S400 standard limits any configuration's maximum cable length to 72 meters. The 6-pin connector is commonly found on desktop computers, and can supply the connected device with power.  See the pictured below.  The picture on the left is the 6-pin male plug.  The picture on the right is the 6-pin female connector.

The 6-pin powered connector adds power output to support external devices. Typically a device can pull about 7 to 8 watts from the port; however, the voltage varies significantly from different devices.  Voltage is specified as unregulated and should nominally be about 25 volts (range 24 to 30).

1394a also standardized the 4-pin connector already widely in use. The 4-pin version is used on many consumer devices such as camcorders, laptops, and other small FireWire devices. Though fully data compatible with 6-pin interfaces, it lacks power connectors.  The picture below shows a 6-pin and 4 pin FireWire connector

The picture below shows a 6 to 4 pin FireWire cable with the 4-pin connector on the left and the 6-pin connector on the right.
This cable is commonly used to connect FireWire devices such as the FLEX-5000, FLEX-3000 or a FireWire based sound card to a laptop computer.

FireWire 800 (IEEE 1394b)
FireWire 800 (Apple's name for the 9-pin "S800 bilingual" version of the IEEE 1394b standard) was introduced commercially by Apple in 2003. This newer 1394 specification (1394b) and corresponding products allow a transfer rate of 786.432 Mbit/s full-duplex via a new encoding scheme termed beta mode. It is backwards compatible to the slower rates and 6-pin connectors of FireWire 400. However, while the IEEE 1394a and IEEE 1394b standards are compatible, FireWire 800's connector is different from FireWire 400's connector, making the legacy cables incompatible. A bilingual cable allows the connection of older devices to the newer port.  The picture below shows a
9-pin to 6-pin bilingual FireWire cable

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Posted Monday, July 28, 2008 by Administrator