Re: Firewire vs USB (WAS: Packing a laptop setup (with trombone) into bags)

[Rainer Straschill <moinsound@googlemail.com>]

Daryl asked:
> USB cables can also carry power, would you suppose that that the same 
>risk applies?

USB uses much lower voltage and power - to be more precise:

USB has 5V of power supply, with the signal lines being in the 0-1V
range. However, pulling signal lines high is used to signal the
transfer speed, so there is a good chance that shorting the 5V power
line with one of the signal lines will not damage the interface
circuit. Also typical semiconductor technology voltage ranges are well
above that, but I don't know whether CMOS input stages are used.

The case is different with Firewire; here, the power supply is
specified at 25V (more specifically: 24 -1/+5V), however, a lot of
laptops only supply their DC supply here. Still, that voltage is
something that could damage your input circuit if a short between the
power supply lines and the signal lines happened.

Solution: use USB. Or use 4-pin Firewire connectors. Or don't use
computers at all ;)

              Rainer