USB 2.0 & External HDDs

[nospoon]

This might sort of a n00bish question but does does the cord length of a USB 2.0 cable used on an external hard drive matter, that is, would the speed be any faster/slower if I were to use a 5 foot cable versus a 20 foot cable? Generally, are shorter cables just recommended? Is there any sort of cut off length?

Thanks

[eyeball]

people say that with 56k the shorter the line you have from the wall to modem the faster your speed so would assume the same thing happens with usb. i guess its like with CAT cables, i think the term is signal attenuation but dont quote me on that

oh and i have no idea what the cut off length is, but i would be interested to know....

Edited May 6, 2006 by eyeball

[nospoon]

people say that with 56k the shorter the line you have from the wall to modem the faster your speed so would assume the same thing happens with usb. i guess its like with CAT cables, i think the term is signal attenuation

Not quoting, just replying

This is why I asked the question too because back in the old school days this was the case...however, I never bothered with it much since I always used those standard cables/wires, and they were pretty short Now I am just wondering about the newer technologies out there...like the USB with the external hard drives or even the Firewire cables too.

So just curious to know what the definitive answer is on that and others likewise

[Andromeda43]

It's just a fact of nature.....most all of our wire is made of copper. It's a pretty good conductor and that's why we use it, but it does exibit resistance to currnet flow. Gold would be better, but it's a little pricey!

The longer the wire the more the loss. (the less the bandwidth)

I can't even get DSL service here at my home, because I live 1000' too far

from the "Switch" to be able to use DSL. There's just too much loss in the old copper wire.

Always for tidyness and best operation keep all lines as short as you can.

I once had a HD that would not work reliably on a data cable of over 9" long.

SATA for instance has a 40" limit to their data lines.

Happy Computing,

Andromeda43 B)

[nospoon]

@andromeda: thanks

yeah, supposedly where I am at DSL is not available either, so I have to pay up the arse for cable modem access. It's funny that they should say DSL is not available, but when I enable my wireless, I see at least three wireless routers with their SIDs as "2WIRE" and I know for a fact 2WIRE is highly prominent in this region for being used with the local DSL provider.

Do you know if DSL has some sort of capacity in terms of users? Which is why they would tell me that it is not available?

I mean, of course, networks have a capacity, but why would they bother to keep advertising it, when they don't have any more "connections" per se (if that were the case)?

I could be saving more than half if I could get DSL...that's how much Comcast is being a monopoly.

Edited May 7, 2006 by nospoon

[Zxian]

I'm not sure about the cutoff length, but the problem comes with the signal strength. If the signal were strong enough, then the length of the cable wouldn't be the bottleneck - your hard drive would be. USB 2.0 can handle 480Mbps (60MB/s) of data transfer - something that most regular hard drives have trouble keeping up with.

[Takeshi]

It's a long while since I did physics but Zxian is on the right track. Signal strength is not the same thing as signal speed (velocity). If I remember correctly, electromagnetic wave travels at the velocity of light down the wire. But it makes sense not to have excessive lengths of cables.

[LLXX]

USB 2.0 cables are not recommended to be over 2m in length.

[Zxian]

It's a long while since I did physics but Zxian is on the right track. Signal strength is not the same thing as signal speed (velocity). If I remember correctly, electromagnetic wave travels at the velocity of light down the wire. But it makes sense not to have excessive lengths of cables.

Correct. Like Andromeda said, there's resistance in the wire. As a result, the longer it is, the lower the signal strength will be at the receiving end.

USB 2.0 cables are not recommended to be over 2m in length.

And there you have your answer.

[nospoon]

USB 2.0 cables are not recommended to be over 2m in length.

Thanks

That's 6 feet for those not verse (like myself) with SI