Herbert Graf wrote:
> > Herbert Graf wrote:
> > > > Andrew Warren wrote:
> > > > > > Looks to me like a market opportunity, particularly for cameras.
> > > > > > If I can get a 100BT card for under $10, putting the chip IN the
> > > > > > camera can't be THAT expensive.
> > > > >
> > > > >     Keep studying the problem; you'll see why USB is better.
> > > >
> > > >    Standalone webcams with built-in Linux based web-server
> > > > connected to intranet. How USB is supposed to be better than
> > > > ethernet to this very much real case?
> > > >
> > > > Mike.
> > >
> > >         Very simple: price.
> >
> > Only if the camera is near a PC.
> > If you need a 150' cable run, it gets awfully expensive,
> > Or you're not -really- running USB on the long path.
> >
> > Robert
>
>         Which is what USB was NOT meant for, I don't know why you STILL don't get
> that. For most users a webcam WILL be near to PC, for the others there is
> ethernet, which is more expensive, or other means (such as WiFi which is
> even more expensive).

Didn't this particular thread start out as someone wanting to extend
USB cabling to way beyond the spec'd length?

If USB is NOT meant to be extended, then why the ready availability of
extension cables and repeaters and USB to fibre/ethernet links, etc. devices?
What is is MEANT for, and what people try to USE if for are of course two
divergent things.

I totally agree that putting a USB camera at the end of a 100' cable is
not in the spec, but when the camera only costs $50 (thanks to USB) people will
spend $100 trying to extend it, rather than pay $400 for an ethernet
camera which may not be compatible with their motion sensing software
anyway. I went down this path several years ago when we were trying to
come up with a very low cost way to put up bolid (bright meteors) cameras
into an observing network. A web camera with suitable sensitivity was
1/10th the cost of CCTV camera feeding coax to a digitizing card, but the
USB cabling just couldn't handle the distance to the roof (120' or so).
The result was a lot fewer observing stations for the same budget.
Journal of The Royal Astronomical Society of Canada, Dec 2003 has an
article on this camera network. It is not available on line.

People are also using web cameras on telescopes (QCUIAG@yahoogroups.com)
so again, they -want- cabling longer than specs allow (remotely controlled
goto scopes).

So Herbert, I long ago 'GOT IT', but people like me will still -try- to
bend the specs to make it work because of it's low cost.
That doesn't change the fact that I hate the poor quality of USB drivers
and the way they stack up in a Winblows box.

Robert

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