Transcript 1394-extra - faculty at Chemeketa

Universal Serial Bus - Applications
1394 Domain
USB Domain
Video Conf
Camera
DSS
“NIC”
Phone
Joystick
Keyboard
DV Camcorder
Mouse
Audio
Personal Printers
Tape Backup
Floppy
Digital VCR
DVD-RAM
USB and IEEE1394 Are
Complementary Technologies
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Universal Serial Bus - Applications

USB Focus on Low Cost, High Volume Applications
USB
is targeted at devices requiring relatively low
bandwidth (10Mb/s or less).
The
USB, tiered star approach is cheap for downstream
nodes, but requires a central host.

IEEE 1394 is more expensive and has a different
design focus.
IEEE
1394 (FireWire) has no central host, and therefore
requires a complete controller at each node.
IEEE
1394 is targeted at applications requiring 100Mb/s+
bandwidth which is not needed for most PC peripherals.
»
Digital VCRs and other consumer electronics require the
bandwidth provided by IEEE 1394.
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IEEE 1394 Background -Tom’s Hardware

IEEE1394 is a high speed isochronous (real-time) serial
standard developed by Apple under the FireWire
moniker. The first completed specification was delivered
by Apple in 1987. This standard was later absorbed into
IEEE1394 in 1995. Requiring no hubs, each bus can
support up to 63 devices and up to 1023 busses can be
interconnected. A very compelling aspect of 1394 is that
it is a peer-to-peer standard, resulting in that a PC is
not needed to connect FireWire devices - in fact the PC
is simply another "peer" in an IEEE1394 link. This is an
unfamiliar notion for most PC users, but, in theory, a
digital camera equipped with a FireWire port could be
connected directly to an IEEE1394 hard drive and the
camera should be able to directly save its files to the
drive. At the recent IDF, components of a home
entertainment center were entirely wired to one another
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using IEEE1394.
IEEE 1394 Background -Tom’s Hardware



A duo of two twisted pair conductors form an IEEE1394 cable. These
cables are similar to those used for 10BaseT Ethernet. Two extra
wires are used to provide juice for those devices that are not selfpowered. Using "fairness" arbitration to ensure that all devices
obtain access to the pipe, IEEE1394 also multiplexes different types
of digital signals like video, digitized audio, MIDI, as well as device
control commands.
Much faster than USB, IEEE1394 can transfer data at up to 400 Mb/s
(50 MB/s), which is half as fast as the new ATA100 standard used for
internal storage. Despite its performance, IEEE1394 is not currently
meant as a competitor to ATA, but is targeted for external devices
where hot-pluggable devices can either obtain their power from the
port (six wire cables must be used) or be self-powered.
While IEEE1394 is much faster than USB and uses very little
overhead, it is slightly more expensive to implement. For this reason,
cheap, low-speed devices such as keyboards, mice, and low
resolution digital camera are best suited for USB, while devices
demanding high-speed real-time service require 1394.
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