That’s the kind of question that doesn’t come up unless you get have all these problems with your firewire drives, and Mac’s Console reports things like “bad node” and you think it’s either the drive or the computer and finally you figure out it’s the BLOODY CABLE.
Computerease Chicago advices you to go looking on the intertubez to try to find out who makes the best Firewire cable (even though Mac phased all that stuff out ages ago and instead of being able to daisy chain FW drives you now have to buy things like THIS to handle all the USB connectors.) And then you come across discussion threads like this one, where people seem quite knowledgeable or at least you hope.
FYI: There are three wire mills that make the vast majority of FireWire IEEE 1394a and 1394b cables.
The actual cabling, #28 AWG signal wires (four data wires, stranded, double duplex, packet switching peer to peer communications) and #20, #22 or #24 AWG power, ground & shield wires, used for almost all FW 1394a cables are virtually the same.
The rub is in the assembly and termination parts, the connectors. Dr. Sam Liu, an upstanding IEEE engineer and owner of Newnex.com Technology Company, is the head of the standards committee at the 1394ta.org and has been since 1999. If there is a FireWire “triad” symbol on the cable terminations or connectors, then its a good one and Dr. Sam probably helped design it and/or certify it.
And suddenly you look at Firewire cables a little bit differently, because–and maybe this is why I find it comforting–there’s an actual person behind it, and there’s even a seal of approval to look for.
Also learned: you can test a cable if you have the right oscilloscope equipment and a good cable will produce an aesthetically pleasing pattern like this.
So to sum up: Cables! More fascinating than you think.