Description: IEEE 1394a/b cable features a 6-pin FireWire male connector at one end and a 9-pin male FireWire 800 connector at the other. The IEEE specification provides total compatibility between the 400mbps and 800mbps busses - which you can now experience for yourself! Mate all your FireWire devices to virtually any machine with any flavor of powered FireWire ports (Including the new Apple MacBook Pro).
RadTech's ProCable M48P allows FireWire 400 and 800 devices to be used on either port:
Use a FW400 hard disk drive on a FW800 port, or an 800 disk on a 400 port. Connect a FW400-based web cam, like the Apple iSight, to your computer's FW800 port to prevent external FW400 HDD data transfer stalls and errors.