[rescue] doubt regarding wireles ethernet...

[Brian Hechinger]

On Thu, Jul 19, 2001 at 09:12:37AM -0400, David Rouse wrote:
> 
> > hello sir
> > my name is narendran..........i am a student of electronics and 
> > communication engg from india.
> > iam planning to set up a wireless connection between a computer in our 
> > microwave lab and a neighbouring network of computers.
> > That isi am trying to make a computer look as if it isone of the lan 
> > computers.....but linked through wireless....i have an idea in 
> > mind......i have a pair of transceivers operating at 434Mhz.
> > which can transmit serial digital data......and receive digital data 
> > serially......
> 
> The Right Thing -- given your equiptment -- is to create a PPP 
> connection, unless someone else has a niftier TCP/IP over serial idea.

he's not there yet.  he's still trying to hook these thing up yet.  plus. he's
not using serial, he's trying to build an "ethernet media translator".

so, to answer this guys question (i'm not an EE and honestly don't know a whole
hell of a lot about this kinda stuff, but i'll do what i can)

due to the high speed nature of ethernet (as compared to say serial) there is
the problem of cross-talk between Tx and Rx.  so to combat that, they stopped
using a common ground.  they also started using impedence balanced lines (hence
the twists, and i don't know if that's the right term, i just made it up, keep
in mind that i am NOT an EE)

so what you need to do, is take Tx+ and Tx- and watch them together as a circuit
and read the bits (high and low) off of them and send those bits to your other
wireless box which would then decode them and turn them back into ethernet
signals and transmit them on the Rx+/Rx- pair.

do it the other way as well, or your network is going to be a little one sided.

i hope that helps.  go find an ethernet specs sheet, there is a lot more to it
that that, but i hope i am pushing you in the right direction.

-brian