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Firewire
Firewire
(IEEE 1394) is a high-speed serial interface
originally developed by Apple.
FireWire
has the following characteristics:
- serial-bus
connection
- six-wire
connection
- 200
Mbs transfers (up to 400, scaleable to 3200
Mbs?)
- isochronous
transfers
- peer-to-peer
network
- up
to 64 daisy-chained devices (up to 15 feet
between devices)
- hot-plugins
- Possible
uses include: digital video, hard drives,
networks
FireWire
can support multiple synchronous transfers so that
a stream of video can occur at the same time as
another transfer without being interrupted.
Firewire is currently available as add-on cards
which cost around $400. Other advantages of
FireWire over SCSI is that it does not suffer from
the termination problems, expensive cabling, and
short chain lengths (15 feet maximum).
Firewire
allows any device to access another on the chain,
so their can be multiple computers on one chain,
and a vcr can connect with a camcorder connected to
the chain. In fact, no host is required; Firewire
can already be used to connect two
camocrders.
Most
professional and prosumer DV devices include
FireWire. Sony has said it intends to use FireWire
to connect their AV and audio equipment and
Yamaha's mLan (a FireWire device) could become a
MIDI replacement.
The
Read Me for Apple's Firewire Enabler includes the
following information:
IEEE
1394 and FireWire support up to 63 FireWire devices
(including computers) connected together. Follow
these guidelines for connecting FireWire devices to
the computer:
- Do
not connect more than 63 devices at one time.
- Do
not connect devices in such a way that any two
devices have more than 16 cables directly
between them.
- Do
not connect FireWire cables in a way that forms
a ring of devices. Do not plug both ends of one
cable into the same device.
- Unused
FireWire connections should be left empty. There
are no terminators for FireWire connections.
- Connect
devices that require power from FireWire
directly to the computer.
- Do
not unplug a FireWire device while it is being
used. For example, do not unplug a FireWire disk
while copying files onto it.
The
Internet
Engineering Task
Force
has an IP
over IEEE 1394 Working
Group,
looking at how the Internet Protocol can be used
with IEEE 1394 Serial Bus to support devices such
as consumer electronics. This could mean a
significant change for video on the
Internet.
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Apr
5, 1999
Digital Origin has a 4-pin to 4-pin
IEEE 1394 cable for transferring video
between two DV cameras. This cable is
available in a 2 meter length for $59.
Call if you wish to request a longer
cable. To purchase, call Digital Origin
sales at 800-572-3487 or go to their
online store.
<www.digitalorigin.com
web page "FireWire
cables">
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Mar
30, 1999
Apple has updated it's Firewire
Enabler. Firewire 2.0 can improve
the quality of video recorded from blue
and white Power Macintosh G3 computers to
DV devices. FireWire 2.0 also contains new
services that enable the use of FireWire
disk drives, printers, and other new
devices. We hope that it fixes some timing
incompatabilities with newer Sony DV
cameras (though it's not specifically
mentioned in the released
documentation.
Power
Macintosh G3 computers can transfer
perfect digital video (DV) on FireWire
when no other devices are using the
FireWire bus. If you have problems with
digital video transfers, make certain that
no other FireWire devices are being used
at the same time.
<www.apple.com
software page "Firewire
2">
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Sony
has an Analog to Digital converter which
you can use to convert existing video to
the DV format. It will also convert DV to
analog formats; the DVMC-DA1. As
far as I know, at the moment (Feb 1, 1999)
Sony isn't selling these in the States
officially yet. They were supposed to
start bringing them into the country, but
I haven't seen any announcement about that
yet.
Akiba
Exports <akiba.giganet.net>
is bringing them into the country but will
only sell them in lots of five or more.
Promax <www.promax.com>
and Berger-Bros.<www.berger-bros.com>
are selling them in individuals lots
(Berger Brothers quoted a price of
$379.99) These are probably consider "gray
market" so there may be no warranty; but
since there's no moving parts in this box
it's probably not a big
consideration.
Akiba's
website says that the DVMC-DA1 is a
"special use" item and production is
slated for 2,000 units per month. There
were plans for an official US release (by
Sony) of the product for PRE-CHRISTMAS 98,
but it didn't happen. They say that they
think the Sony USA MSRP will be $499.99.
That report is one month old and
converting the Japanense price in the
original press release for the product to
US$ makes for a price of $280 plus
whatever mark up Sony would
add.
The
unit was thought to support PAL, but that
does not appear to be the case.
<www.sony.co.jp
product press release "DVMC-DA1">
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Apple
now includes two Firewire ports on it's
latest Desktop G3
computers.<www.apple.com>
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Looking
for a Firewire cable? They can be
expensive. John Richey has been
maintaining a page of Firewire sources and
prices:
<"Firewire
Cables">
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See
also USB
USB
has the following characteristics:
- serial-bus
connection
- four-wire
connection
- 12
Mbs transfers
- isochronous
transfers
- single-computer
host
- up
to 127 daisy-chained devices (up to 15 feet
between devices)
- hot-plugins
- Possible
uses include: hubs, keyboards,
scanners,
USB
is unusable for uncompressed high-data-rate devices
like near-broadcast quality video
cameras.
last
updated: 4/5/99
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