LaCie Mobile Drive
Hi-Speed USB 2.0
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What Are The Ideal Applications For
Hi-Speed USB 2.0?
Digital cameras, CD/DVD drives, hard drives and
scanners will all benefit from the added bandwidth and
performance gains of the new implementation of the
USB standard. Hi-Speed USB 2.0 provides the neces-
sary fast data transfer rates that today’s devices require,
and combines the earlier specifications so older devices
that operated under the original USB standards will still
work with Hi-Speed USB 2.0.
Will USB Devices Run Faster When
Connected To A Hi-Speed USB 2.0 Bus?
Unfortunately, no. The Hi-Speed USB 2.0 specifica-
tion is specifically written to allow developers to design
higher speed peripherals that can take advantage of the
extra bandwidth. USB devices, though, will still operate
at 12Mb/s at full-speed and 1.5Mb/s at low-speed on a
Hi-Speed USB 2.0 bus. Even though USB devices won’t
run any faster, they can work alongside Hi-Speed USB
2.0 devices on the same bus. However, if you plug in a
Hi-Speed USB 2.0 device to a USB bus, the speed of
the Hi-Speed USB 2.0 device will decrease to 12Mb/s.
What Is A USB Hub?
Technically, you can connect up to 127 devices to a
single USB bus. For more than two devices, though, you
must make new connections using a peripheral called
a “hub.” A hub, which you hook up directly to a USB
connector on your computer, usually has 4 or 7 output
connections enabling you to connect the same number
of peripherals. One of the hub’s main functions is to re-
generate signals that lose strength as they are transmit-
ted via the USB cable. By connecting yet another hub to
a connector on the existing hub, you can then plug in a
new set of peripherals etc, up to a maximum of 127.
Some hubs have no power supply and others are
self-powered. When you choose a hub, opt for the self-
powered variety, as they have their own AC adapter.
The most powerful hubs provide 0.5A of power to each
port.
If you buy a hub, make sure that it supports per-port
switching. This function prevents the entire chain of pe-
ripherals from freezing up if one of them is not working
properly or is down.
Will Hi-Speed USB 2.0 Devices Work
On USB Hubs And Vice Versa?
You can use your Hi-Speed USB 2.0 devices with
USB hubs, but the peripherals will be limited to USB
performance levels.
There are Hi-Speed USB 2.0 hubs that are able to
communicate in three modes: high-speed (480Mb/s),
full-speed (12Mb/s), and low-speed (1.5Mb/s). Hi-
Speed USB 2.0 is backwards compatible, so you will
be able to connect USB devices to Hi-Speed USB 2.0
hubs; however, the USB devices will still maintain their
normal performance levels (i.e. 12 Mb/s).
In order to achieve the fast data transfer rates of Hi-
Speed USB 2.0, you must connect your Hi-Speed USB
2.0 device directly to a Hi-Speed USB 2.0 port on ei-
ther a computer or hub.
For more information about the USB interface,
please visit:
www.lacie.com/technologies
TeChNICAl NOTe:
Avoid using USB connectors found on certain pe-
ripherals such as keyboards. These are passive (or
passthrough) connectors that lead to power loss
and unstable operation.
Only use USB cables shorter than 5 meters (ap-
proximately 15 feet). Using longer cables may
cause the peripherals to malfunction due to exces-
sive reduction in electrical signal strength.
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