On 12/31/06 4:26 PM, Peter Sealy wrote: > I have an external 400 Firewire HD which I connect to my TiPowerBook > as necessary to clone/backup my PowerBook system. When I buy a new > computer which has Firewire 800 speed will my 400 HD still run on the > new computer albeit at the slower 400 speed. I know those speeds are > theoretical but I guess what I am asking is if a 400 HD is compatible > with an 800 port on a new computer. I hope I have expressed that > clearly. Firewire 400 and Firewire 800 have different connectors -- they are not the same connector with different speeds, as USB and USB 2.0 are. They are physically different shapes, so you cannot plug a Firewire 400 cord into a Firewire 800 jack, and vice versa. This Ohio State website illustrates with pictures. <http://8help.osu.edu/1249.html> Hope this helps! peace, Linda