Re: Serial over CAT5

[Grimshaw Stuart <stuart.grimshaw@xxxxxxx>]

I too am looking at using the Dallas 1-wire stuff. It's fairly high on
my list at the moment, though the lack of somewhere to buy even the
simplest electronics equipment in Blackburn is a serious limiting
factor. (it took me a week to find some solder!!)

Jon Whiten sent me a link to the Dallas site, I also searched the site
and came up with the 1-wire net design guide
(http://www.dalsemi.com/TechBriefs/tb1.html),
there are several circuit
diagrams on there for interfacing to PC's, ranging from a circuit that's
basically just 4 diodes, to a full blown opto-isolated mother!!

There's also some source code & drivers on http://www.ibutton.com for
all flavours of windows and Linux too!!

Like I say though, this project will probably take an age as there is
nowhere to source the stuff in Blackburn, I'll have to get it from RS
online or somewhere...

Stuart Grimshaw,
System Administrator,
Community, Leisure & Cultural Services Dept.
Blackburn with Darwen Borough Council.

t:01254 587235
f:01254 660236

>-----Original Message-----
>From:	Nigel Orr [SMTP:nigel.orr@xxxxxxx]
>Sent:	Friday, March 03, 2000 12:34 PM
>To:	ukha_d@xxxxxxx
>Subject:	[ukha_d] Re: Serial over CAT5
>
>At 12:16 03/03/00 +0000, you wrote:
>=20
>>A multimeter, a multimeter, my kingdom for a multimeter...=20
>
>Get yourself down to your local Maplin, and buy the cheapest meter they
>have.  It costs about =A37, it's fairly naff, but will probably do =
everything
>you need a multimeter to do.  I've got a better all-singing/all-dancing
=
one
>that I usually use, but the little analogue one still wins =
occasionally!
>
>Who needs 1% accuracy?  Maybe on one occasion in 1000?  Just about =
every
>time I need a multimeter, it's either to see relative changes, or for a
>quick 'working' or 'not working' answer... If it had a 1 digit display,
>that would probably be enough for most occasions. =20
>=20
>>>I've got a couple of 9-pin serial to CAT5 adapters
(unfortunately =
sealed=20
>>>units) and was wondering if anyone knew which wires are used
from the =
CAT5=20
>>>end. I assume that it's not all of them so could I pass the
audio =
signal=20
>>>from the line out on my sound card down it too? From my
knowledge of=20
>>>serial comms were usually talking pins 2,3,7 (on a 25 way) what
about =
a=20
>>>9-pin?
>
>It depends what they implement- just Tx and Rx would only need 2 pairs,
=
but
>if it also passes 1 handshake in each direction, it might use all 4.
>That's assuming it's all balanced, they could have bodged it onto 3 =
wires
>if it doesn't need to work over long distances (more than 5-10m say).
>
>>>One other thing... can I pass 5 volts down CAT5 safely... would
the=20
>>>voltage at the other end of say 100m length of CAT 5 drop =
significantly?
>
>You can pass mV down cat-5 safely... if it's high impedance you will =
get
>noise added though...  what are you wanting to use it for? =20
>
>If it's the ibuttons again (piecing together a number of your =
postings!),
>ISTR working out they would run off 150m odd of cat-5. =20
>
>Contact Dallas and ask them if they have tested it on cat-5 if you =
don't
>fancy ploughing through calculations or data sheets... they've been =
very
>helpful in the past.  ibuttons are in a middling position on my
>ever-growing todo list (ie lots of ideas and designs, no time to build
=
them
>yet!), so keep me posted on progress!
>
>Nigel
>
>
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