I do not think this cable does what its vendor thinks it does.

January 30, 2006 5:57 PM

Mystery cable claims to connect USB and firewire. What does it really do?

We all know (it's been discussed here a few times, but my search isn't turning up the reference) that there's no such thing as a Firewire to USB cable. So what is this?

posted by tangerine to computers & internet (14 comments total)

Very odd.

My guess is that it's for video cameras (or something) where the FireWire port doubles as a USB port. I've no idea if such things exist, but it's the only thing that makes sense.

It could also be the cable is for a device that uses a FireWire connector as a makeshift mini USB port. Again, I don't know of any devices that actually do this.
posted by cillit bang at 6:04 PM on January 30, 2006

A quick Google search came up with this.

However, it could be a USB A to USB B cable, where the B connector has been bent down.
posted by Jim T at 6:05 PM on January 30, 2006

The pin count is the same (4 on each), but FireWire uses a 30 volt power line and USB uses 5 volts, so any devices you hooked up would either be woefully underpowered or get fried, regardless of the data compatibility (which is probably nil).

There are no 'guts' in between the two ends of the cable, either, so no magic, only pins getting wired together. Sounds like a pretty dangerous product to me.

Jim T's answer seems plausible, but reviewing some pictures of A to B adapters, 4 pin FireWire cables, and the pics from the auction suggests that the small end is in fact a 4 pin FireWire plug.

The cable he links has 'guts' in the middle that might actually allow it to work, albeit only for transferring DV footage.
posted by jedicus at 6:13 PM on January 30, 2006

I have one of these cables (I think). It came with my Sony mini-DV video camera.
posted by soiled cowboy at 6:19 PM on January 30, 2006

probably a proprietary cable for a camera, or a handy way for a half-way savvy eBay seller to sell something to fry other people's devices. the firewire end's crimp is way more pronounced than any 4-pin firewire connector I've ever seen (which is, admittedly, not very many). that may not mean anything, though, other than it being a crappy firewire connector.
posted by mrg at 6:20 PM on January 30, 2006

Oops. I should have said I don't have one of those cables. What I have, and what the pictured cable may be, is a 5-pin mini USB to USB.
posted by soiled cowboy at 6:30 PM on January 30, 2006

Bizzare. I suppose a couple chips could do the conversion, but it dosn't look like there's anything of the sort on that cable.
posted by delmoi at 6:41 PM on January 30, 2006

It probably belongs on this page. (warning, don't try this at home)
posted by b1tr0t at 7:17 PM on January 30, 2006

4 pin Firewire ports don't have the power conductors, so that cable probably wouldn't burn anything out.
posted by zsazsa at 7:26 PM on January 30, 2006

zsazsa is right, of course. But then, if it can't even transmit power then I'm really not sure what it could possibly be for.
posted by jedicus at 8:52 PM on January 30, 2006

Probably answered here.
posted by fatllama at 9:07 PM on January 30, 2006

Could it be for connecting a firewire using device to a non-firewire having computer or maybe vice versa? One of the connectors is the end that would normally be in your computer.
posted by fshgrl at 9:26 PM on January 30, 2006

Radioshack used to carry a Firewire to USB cable, cant find it now, as far as I know (I have checked with two a+ techs) it had no purpose. But I did find this .
With regard to the cable mentioned in the question, I would bet that cillit bang got it right.
posted by Binliner at 9:39 PM on January 30, 2006

Thanks, everyone. I was tempted to write to the sellers and ask for clarification, but I doubt they know or care. I guess the mystery remains.
posted by tangerine at 9:16 AM on February 1, 2006