If you've asked yourself questions like: "I have a Fw400 device, can I plug it into a Fw800 port?" or "how does it work putting several Fw devices in chain?", this is a must-read.
Metric Halo guys have just published a helpful tech-note. In their words: "there is a lot of "wisdom" on the Internet regarding Firewire and how it does (and doesn't) work. Unfortunately, much of it is incorrect and leads to a lot of confusion"...

Read the full document here.