[mythtv-users] USB Extenders, and other USB stuff

[Allen Edwards]

On Thu, Feb 26, 2009 at 12:43 PM, Robert Johnston <anaerin at gmail.com> wrote:

> On Thu, Feb 26, 2009 at 14:27, Brian Wood <beww at beww.org> wrote:
> >
> > Recently there was some discussion here of extending USB cable runs
> beyond the
> > normal distances.
> >
> > I found this site, which has a lot of USB-related gear, including
> extender
> > units that can push the distance to close to a quarter-mile. Also some
> other
> > stuff, including a waterproof USB GPS unit (for scuba divers who get lost
> > easily?).
>
> I'd say the waterproof USB GPS would be for external mounting on a
> car, or boat, say.
>
> > A large selection of USB-to-serial devices, including units with 4 serial
> > ports. Don't know if they will work with Linux, or control a DirectTV
> box.
> >
> > Also extenders that will handle USB 2.0 (apparently a lot of them will
> not).
> >
> > Thought some folks here might be interested:
> >
> > http://www.usbstuff.com/
>
> In theory, all you need is an active hub every 30m or so, to boost the
> signal and repair the droop from the cable. Using a 4-port active USB
> hub, and given USB's 255-device limit, that gives you a potential
> range of ((255 - 3)/4)*30, or 1,890m (Just under 2km). Latency may be
> an issue, with cable runs that long, but if you really need to send
> signals 2km, there's better ways of doing it. Still, that would give
> you full USB2.0 speeds.
> --
> Robert "Anaerin" Johnston
> Sent from: Regina Saskatchewan Canada.
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>


Wow, there is a spec on this and you are quoting something way beyond what
is allowed.   Here is a quote from the FAQ on USB.org.

Q3: How far away from a PC can I put a USB device?
A3: With the maximum of 5 hubs connected with 5m cables and a 5m cable going
to your full speed device, this will give you 30m of cable (see section
7.1.19 for details). With a low speed device, you will be able to get a
range up to 27m, depending on how long the device's cable is. With a
straightforward cable route, you will probably be able to reach out 25m or
so from the PC.

I know it will work in excess of this spec as I have a 15 ft passive
extension cable with a 6 foot normal cable plugged into it and it works but
2KM is way beyond what is going to work.

As far as where to get this stuff, you can buy it for $25 at the site
suggested by the OP or you can buy it for under $9 like this one
http://www.monoprice.com/products/product.asp?c_id=103&cp_id=10303&cs_id=1030304&p_id=2779&seq=1&format=2

Cheers,

Allen
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