RE: Re: IR over cat5

["Ian Lowe" <ian@xxxxxxx>]

ahh, you miss my point..

Using RS232 3-wire: TX, RX, GND

The electrical signal on TX is not a voltage relative to the local ground
of
the reciever, it's relative to Signal Ground, and if the signal ground wire
has been wound around the actual signal wire, then both have been subjected
to *roughly* the same noise,

Hence the voltage on the signal line relative to signal ground when the
signal ground has been twisted with it is closer to what it should be than
if you had simply passed three totaly discrete wires through free space.

I know that balanced kit uses this effect specificaly, but AIUI, the effect
is present even when using a twisted pair for 1-wire transmission.

isn't this effect why 80-core ATA-100 drive cables have alternate
signal/ground wires across the width of the cable?

Ian.


-----Original Message-----
From: bill.mcmahon@xxxxxxx [mailto:bill.mcmahon@xxxxxxx]
Sent: 18 February 2002 17:36
To: ukha_d@xxxxxxx
Subject: RE: [ukha_d] Re: IR over cat5


But thats if your using 'balanced' transmission like RS422, here its
RS232C which is unbalanced, ie 1-wire for TX and 1-wire for RX.

Thats my 0.02 Euro worth.

Bill

-----Original Message-----
From: ian@xxxxxxx [mailto:ian@xxxxxxx]
Sent: Monday, February 18, 2002 4:23 PM
To: ukha_d@xxxxxxx; ian@xxxxxxx
Subject: RE: [ukha_d] Re: IR over cat5



I always thought that if you are using CAT-5, and you use one pair for
TX
and a pair for RX, and common the grounds, then you can get a bit of
benefit
>from

as the ground line and the signal line are exposed to (basically) the
same
induced noise along the cable path, hence leaving the original signal
"untouched" (or less touched at any rate)

Ian



-----Original Message-----
From: Mark Harrison [mailto:Mark.Harrison@xxxxxxx]
Sent: 18 February 2002 16:14
To: ukha_d@xxxxxxx
Subject: RE: [ukha_d] Re: IR over cat5


Remember that CAT5 isn't (normally) shielded!

It's _balanced_, but you need a lot more than a cheapy convertor to take
advantage of that!

Mark Harrison
Head of Systems, eKingfisher