Backwards compatibility? USB, Firewire, SATA

[Artic_Kid]

We've heard about three new standards that are 'faster' than the previous:

USB 2 (replacing USB 1)
Firewire 1394a (replacing Firewire 1394b)
SATA 2 (replacing SATA 1)

(Those are somewhat informal names, but you get the idea.)

I hear those standards are "backwards compatible" with the previous standard. I presume that means the old equipment can be used on motherboards having the new interface/bus. (Correct me if I'm wrong there. I may be wrong about 1394b, which uses a different connector than 1394a???)

Here is my question. When you take equipment having the old standard and connect it to a motherboard having the new standard, does it cause the communication controller to REVERT BACK to the old (slower) standard for all the devices on that port/channel? Does a mix of new peripherals and old peripherals cause it to SLOW-DOWN to the speed of the old peripherals?

In other words, what ill-effects are there for connecting old gear to a new motherboard having the new standards? (That is actually three questions, one for each standard: USB, Firewire, and SATA.)

Thanks for your help.

[bobbyzero]

USB 2: Generally only the port with the USB1 device connected drops down to USB1 speeds - so if you connect a USB1 hub to a USB2 port, everything connected to that hub will run at USB1 speed.

If you're plugging USB1 stuff into a USB2 hub, depends on the hub but generally just that device runs at the USB1 speed