Firewire
or USB2.0 this is the question?
Many people
have asked us if it is better to buy a digital camera
with firewire (IEEE1394) or USB2.0 interface. The answer is it is
very application
dependent.
Q How easy is it to install a
USB camera?
A USB2.0’s main attraction is that it makes adding peripherals to
your computer
incredibly easy. It enables you to connect your camera to the
outside of the
computer so you don't have to open your PC. A USB2.0 camera simply
plugs right
into the port and works. You don’t need to install a card; you
don’t even need to
turn off your computer—USB2.0 devices are completely
hot-swappable. Because
USB also distributes power, many cameras don’t require a separate
power supply,
although a bus-powered device must be attached upstream to either a
host PC
or a separate power supply.
Q
Will a USB2.0 camera work with any type of USB2.0 port on my PC?
A No. You need to
know the USB2.0 must
be “native” on the motherboard: USB2
PCI cards (desktops) and USB2 PC cards (laptops) will not support
the camera acquisition.
Q
Can you tell me more about USB2.0?
A Hi-Speed USB 2.0, has gained wide acceptance in the camera industry for high
speed image streaming to PCs. It increases the speed of the camera
-to-PC
connection from 12 Mbps to 480 Mbps, or 40 times faster than USB
1.1. This
increase in bandwidth enhances the use of external peripherals, such
digital
cameras that require high throughput.
Q
Can you tell me about Firewire™ or IEEE1394?
The IEEE 1394 standard is a
fast, scalable, low-cost digital interface. Originally
conceived by Apple® Computer and developed within the IEEE 1394
Working
Group. It is generally referred to as FireWire™— the Apple
trademarked name—although other companies may use different names, such as I-link
and Lynx,
to describe IEEE 1394.
Q
OK so both USB2.0 and IEEE1394 offer high speed data transfer and
from what you said earlier USB2.0 seems really easy to use so when
should I use a firewire camera instead?
A Because FireWire is a peer-to-peer interface, it makes it possible
to dub from
one device (a digital video camera, for instance) to another without
a computer.
It also enables multiple computers to share a given peripheral
without any special
support in the peripheral or the computers.
FireWire supports data rates of 100, 200, and 400 Mbps, (and recently extending
beyond Gbps although camera technology has to catch up before these
high
data rates could be useful in industrial imaging). It supports up to 63 devices
with a maximum cable length of 4.5 meters between devices. The
maximum
number of hops in a chain is 16 for a total maximum end-to-end
distance of 72
meters. The IEEE 1394 standard supports daisy chaining and branching
or
peer-to-peer implementations. Connections can be free-form, mixing
branches
and daisy chains.
In addition to its high speed,
FireWire supports isochronous, as well as asynchronous,
data delivery, providing a guaranteed data rate without lags or
slowdowns.
Because the standard supports guaranteed delivery of time-critical
data, it enables
applications to use smaller buffers, lowering costs.
This makes it ideal for
applications such as digital video transmission, which
demands real-time data transfer. FireWire cable is lightweight,
flexible, and
inexpensive—a vast improvement over bulky and expensive LVDS or
Cameralink
cables.
Q
Ah! YES cabling. I have heard there are two types of firewire
connection.
Is that right?
A Yes.
There are two types of FireWire connectors: 6-pin and 4-pin. The
6-pin
connector, usually found on computers, provides two pairs of wires
for signals
and one pair of wires to provide power to external equipment. Most
FireWire
cameras draw their power directly from the interface.
Q
So how would summarise the differences between IEEE1394 and USB2.0
when related to camera technology?
A While USB2.0 and FireWire (IEEE1394) seem
similar, they are intended to
fulfill different market and cost needs. IEEE1394 has the potential
to move
more data in a given amount of time. Applications that are best
suited for
IEEE1394 are moving high resolution images at the highest possible
speed
within the bandwidth limitation and are ideal for industrial
applications where
external control of image capture is required. USB2.0 is appropriate
for
applications do not make heavy demands on the bandwidth.
For information on the cameras available with
FireWire or USB2.0 interfacing
please visit the camera
section of our web site.
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