im a little confused. i read on the usb.com faq (among many other places) that the maximum length allowed by the usb spec is about 15 feet. but ive seen usb cables longer than that for sale all over the web. i even found one that was 35 feet long. so whats the deal? why would any company produce cables that wont work according to the usb spec?
35 foot long usb cable?
Jul 28, 2003
4 Replies
im a little confused. i read on the usb.com faq (among many other places) that the maximum length allowed by the usb spec is about 15 feet. but ive seen usb cables longer than that for sale all over the web. i even found one that was 35 feet long. so whats the deal? why would any company produce cables that wont work according to the usb spec?
There are some special long USB cables which are not actually cables, but more like a combination of active electronics (USB repeater) and cable. This kind of special cable can exceed the 15 feet USB cable length limit.
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at
http://www.epanorama.net/
It's also possible to go beyond the stated limit of the USB spec IF the high-speed mode ("high-speed" in this case being the full 12 Mbit/sec rate of the original USB 1.0 spec, not the USB 2.0 rates) is never used and the link is restricted to just the 1.5 Mbit/sec slow rate. But while it would work, it's not technically compliant with the 1.0 spec, which I believe required all USB cabling to handle the original max. speed.
Bob M.
In article , snipped-for-privacy@addressinvalid.com mentioned...
And to compound the situation, the USB 2.0 spec was designed to work with USB 1.0 cables, which means that any cable that doesn't meet 1.0 spec will not work at the 480 MB 2.0 speed, which is 40 times faster than 1.0.
What irks me is that the stores are pitching these "USB 2.0 cables", which is as much marketing hype as the "Digital speakers". If the cables simply meet USB 1.0 specs, they will work at 2.0 speed.
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