Several manufacturers have implemented the IEEE 1394 standard largely as propri-
etaryandlicensedinterfaces.Themorepopularofthesearei.Link(Sony),Lynx(TexasIn-
struments), and FireWire (Apple Computer). Of these, the FireWire has been the most
commonly implemented, having been licensed by PC manufacturers for use on non-Ap-
ple computers. The generic version of the 1394 standard is called the High Performance
Serial Bus (HPSB).
An IEEE 1394 connector looks something like a USB connector, except that it is a bit
largerandabouthalfwaybetweenrectangularandsquare.Figure19-12showsaFireWire
connection from a Nintendo Gameboy.Defining the 1394 Bus
The IEEE 1394 port has become the standard link between PCs and consumer electronics.
Using a 1394 port, a digital video camera can be used to capture video content and then
play back the video after it has been edited on a PC.
The IEEE 1394 bus shares several characteristics with the USB interface. They are both
high-speed, Plug–and-Play, hot-swappable interface buses. However, 1394 supports
isochronous (or real-time) data transfers. In an isochronous transfer, data is transferred
within very tight time constraints. This type of data transfer ensures that all parts of the
image arrive together. This is very important for data with audio and video elements,
such as with multimedia data or images directly from a video camera.
The 1394 is faster and more expensive than the USB interface, which is why it is used
primarily for devices that require larger data transfers in a shorter time, such as a digital
video camera. Another and perhaps more dramatic difference is that 1394 is a
peer-to-peer interface that does not require a host system. The 1394 interface bus can op-
erate quite well with no PC at all. A video camera can easily support and power several
devices on a common interface, as illustrated in Figure 19-13. In fact, the IEEE 1394 bus is
able to support up to 63 external devices.Chapter 19: Ports and Connectors^497
Figure 19-12. The IEEE 1394 (FireWire) connector