09-02-2008, 08:13 PM

I have a MacBook Pro with a Firewire 800 (9-pin) port and an external Western Digital hard drive which only has two Firewire 400 (6-pin) ports.

Does this mean I cannot run Firewire 800 to this external hard drive? Even if I have a 9-pin to 6-pin cable? If so, what is the point of a 9-pin to 6-pin cable?

Thanks in advance.

Kit

09-02-2008, 08:23 PM

The adapter simply lets you use a Firewire 400 device because the connector designs are very different. It doesn't magically make a slower device faster.

09-02-2008, 08:58 PM

So unless the external hard drive has an 800 port there is no way of it running at 800 speed right?

So should I just use a 6-pin to 6-pin cable?

09-02-2008, 09:34 PM

Originally Posted by kitster79

So unless the external hard drive has an 800 port there is no way of it running at 800 speed right?

Exactly. Both devices have to use the same specification, otherwise they step down to the least common denominator.

So should I just use a 6-pin to 6-pin cable?

Yep.

09-02-2008, 10:31 PM

Thanks very much.

09-03-2008, 05:41 PM

Always the slower speed wins, FW800 runs at 400 with a 400 device, USB2 runs at USB 1 with a USB 1 device, memory PC133 RAM runs at 100 bus speed if installed with PC100 RAM etc etc. Things are backwards compatible not upward.

03-06-2011, 12:44 AM

Originally Posted by cwa107

Exactly. Both devices have to use the same specification, otherwise they step down to the least common denominator.



Yep.

really? wouldn't it be a 9-6 pin cable?

03-06-2011, 01:02 AM

Originally Posted by freakvent

really? wouldn't it be a 9-6 pin cable?

Yes, you can use an adapter cable, but that doesn't mean that you'll get FW800 speeds out of a FW400 bus. The two are compatible, but the least common denominator of the devices you're connecting wins.

03-06-2011, 02:08 AM

Originally Posted by kitster79

So unless the external hard drive has an 800 port there is no way of it running at 800 speed right?

Exactly. Your external hard drive is a Firewire 400 device. Firewire 800 is definitely backwards compatible with a Firewire 400 device, but you can never get a Firewire 400 device to perform at Firewire 800 speeds.

Originally Posted by kitster79

So should I just use a 6-pin to 6-pin cable?

If your Macintosh only has Firewire 800 ports (9-pins), and your external device only has Firewire 400 ports (6-pins), you will need either an adapter or a bilingual cable to join the two, *not* simply an ordinary Firewire 400 6-pin to 6-pin cable.

I recommend this:

6-foot, 9-pin to 6-pin bilingual FireWire 800 to FireWire 400 Cable
$4.88
For only $3.96 each when QTY 50+ purchased - 9 PIN/ 6PIN BILINGUAL FireWire 800 - FireWire 400 Cable, 6FT, CLEAR | 9 - 6 pin IEEE-1394B Firewire Cables

Just to be absolutely clear, YES!, you can use your Firewire 400 drive with your Mac that only has Firewire 800. But you will need either an adapter or a bilingual (9-pin to 6-pin) cable to mate one with the other.

___________________________________________

Randy B. Singer
Co-author of The Macintosh Bible (4th, 5th, and 6th editions)

Macintosh OS X Routine Maintenance
OS X Maintenance And Troubleshooting
___________________________________________

03-06-2011, 02:20 AM

Originally Posted by cwa107

Yes, you can use an adapter cable, but that doesn't mean that you'll get FW800 speeds out of a FW400 bus. The two are compatible, but the least common denominator of the devices you're connecting wins.

true, i was just reacting to the statement "yep" in reply to "So should I just use a 6-pin to 6-pin cable?". no worries, i think we've all got it sorted now cheers.

03-06-2011, 02:25 AM

Originally Posted by Randy B. Singer

... you will need either an adapter or a bilingual cable to join the two, *not* simply an ordinary Firewire 400 6-pin to 6-pin cable.

yep, that's what i was reacting to too. cheers