[Sussex] DB9 to RJ45 - minicom?

[Steven Dobson]

John

On Sat, 2006-08-19 at 13:18 +0100, John Crowhurst wrote:
> On Sat, August 19, 2006 12:50, Nicholas Butler wrote:
> > http://www.makezine.com/01/5in1cable
> >
> > All ideas and credit for this go to Make Magazine, Mike Ossman ,  but
> > thanks for jogging my memory !
> 
> Yes, but this makes a serial cable using RJ45 connectors, there is no way
> to use the ethernet port to work as a serial port.

This is correct.  A modern day twisted pair ethernet port (as apposed to
the old BNC MDI or 15-pin AUI connectors) use different hardware
configuration to send and receive data.  IIRC (I'm sure a better
hardware guy here will correct) twisted pair uses voltage differences
between a pair of wires to send the data signal.  twisted pari ethernet
uses two pairs of wires, one for send the other for receive.

Good old serial, at it's simplest uses only three wires.  One for
transmit, one for receive and a common ground.  If it uses other wires
these are used only for handshaking and can be configured to be ignored
by the hardware.

While it may be possible to build a unit that could convert the
electrical signals between the two standards that is only the start of
the problem.  The electrical interconnect is just one of sevel in the
OSI seven layer model[1] - the physical.

Steve

[1] http://en.wikipedia.org/wiki/OSI_model

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