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'Off Topic Ethernet Question.'
2000\02\03@223449 by Andrew Hooper

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Sorry for the off topic question, but someone here may know the
answer to this one.

What is the output on a standard Ethernet card?, the RJ45 has
4 used pins I know they are rx1 rx2, tx1 tx2, but would it be possible
and I know they are 120ohms.

The question is, whats stopping us from using a small rx/tx RF module
and using two Ethernet cards as a wireless interface, Yes I know that
your not going to get 10mb but for some stuff like terminal communications
process control and other stuff its not going to matter.

The idea came to me when I discovered a schematic for an inexpensive
laser RS232 transceiver.

In the environment IM trying to setup this control system in we are not able
to
use Ethernet cables or wired networks due to the machinery.. Its an EDM
machine, and the RF in the room is WAY to high, the PC is in a Faraday cage
because we originally had trouble with it locking up :(.

Regards
Andrew Hooper

2000\02\04@002340 by Randy Glenn

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Could you please tell me where to get a copy of this RS232 "laser"
transceiver schematic? It sounds very interesting - I might be able to use
it to finally defeat Austin Powers. <return pinky to mouth>

-Randy Glenn
E-Mail: spam_OUTPICxpertTakeThisOuTspamyahoo.com
Web: http://i.am/PICxpert

Currently wondering why I can't get in to Safe Mode - where's a Mac when you
need it?

{Original Message removed}

2000\02\04@025245 by William Chops Westfield

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   The question is, whats stopping us from using a small rx/tx RF module
   and using two Ethernet cards as a wireless interface, Yes I know that
   your not going to get 10mb but for some stuff like terminal communications
   process control and other stuff its not going to matter.

Most of the wireless rx/tx modules operate at 2400 to 64000 bits per second,
which is closer to your async port speed than ethernet (by quite a large
margin.)  Might as well just use the async ports with SLIP or PPP.  They
should talk ok to rx/tx modules, or to a TNC for use with longer range
amateur radios.

In case you hadn't noticed, 1Mbps and higher wireless "home area" networks
are becoming commercialized - you can get it all for a couple hundred $$.

Wireless metropolitan area nets are also available, but you'll pay monthly
service fees and I don't know how much for airtime (maybe 0 for some, and
others seem to be based on cellular modems at typical cellular rates.)

I'm not sure what the advantage of a proprietary scheme would be...


BillW

2000\02\04@093403 by M. Adam Davis

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I think you answered your own question about what would keep you from using an
rx/tx RF module...

Andrew Hooper wrote:
Q: whats stopping us from using a small rx/tx RF module
A: Its an EDM machine, and the RF in the room is WAY to high

However, I would suggest you use *shielded* cat5 cable (most cat5 sold is
unshielded) and that you go with 10baseT (100baseT may be more susceptable to
the noise in the room)

Most of the home phoneline and wireless networks were made for the relatively
low electrical noise of the (average ;-) home, and will likely have bad results
in your intended environment.

Also, you can use CAN for computer networking, which is intended for high noise
environments, and is very robust with hardware error correcting etc.  It can go
much faster than your typical RF solution.

I hope this helps!

-Adam

Andrew Hooper wrote:

> whats stopping us from using a small rx/tx RF module

> Its an EDM machine, and the RF in the room is WAY to high

2000\02\04@111759 by jamesnewton

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www.alphalink.com.au/~derekw/upntcvr.htm Realtime Control's UPN Laser
Transceiver
http://home.vicnet.net.au/~upnet/ a laser based network

more at:
http://204.210.50.240/fiberoptics.htm

Also, please use [OT] rather than Off Topic so that people who are short on
time can use an automated system to filter their PICList email.
---
James Newton .....jamesnewtonKILLspamspam@spam@geocities.com 1-619-652-0593
http://techref.homepage.com The Technical Details Site.
Members can add private/public comments/pages ($0 TANSTAAFL web hosting)


{Original Message removed}

2000\02\04@150340 by paulb

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Andrew Hooper wrote:

> In the environment IM trying to setup this control system in we are
> not able to use Ethernet cables or wired networks due to the
> machinery.. Its an EDM machine, and the RF in the room is WAY to high,
> the PC is in a Faraday cage because we originally had trouble with it
> locking up :(.

 You've just told us then, that there's *no way* you could consider
using an RF network of any kind or form in there.

 Fairly obviously, you'll need fibre optic links, so go search for
those.  I suspect Ethernet using 10Base-2 and fully-shielded cable and
connectors would actually work as a wired option, but the fibre sounds
easier to deploy.

 If as mentioned, you don't really need Ethernet speed or multiple
branches, than plain comms speed (115,000 Baud) fibre should do.
--
 Cheers,
       Paul B.

2000\02\04@164443 by Andrew Hooper

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Sorry for not being a little clearer.

The Wireless connection was for another project and not for the EDM
machine.

I have tried shielded Cat5 but was not successful.

Doh!, did not even think of using fibre, this will solve the problem :)

Thanks for the help
Regards
Andrew Hooper
{Original Message removed}

2000\02\05@062233 by paulb
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Andrew Hooper wrote:

> Doh!, did not even think of using fibre, this will solve the problem
> :)

 ;-)
--
 Cheers,
       Paul B.

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