Re: P4C800-E DL Lan Disconnects
- From: "Barry" <barry@xxxxxxxxxxxxx>
- Date: Sat, 1 Oct 2005 23:25:41 +0100
Thanks again for this info, I'm climbing the mearning curve.
Barry
"Paul" <nospam@xxxxxxxxxx> wrote in message
news:nospam-0110051408350001@xxxxxxxxxxxxxxxx
> In article <t-ecnYULQNhrPKPeSa8jmw@xxxxxxxxxxx>, "Barry"
> <barry@xxxxxxxxxxxxx> wrote:
>
>> Thanks for that, I have another PC, I'll have to read your notes
>> carefully.
>> The Firewire doesn't work either although I gather it is a bit sniffy on
>> these boards anyway. Since the LAN and the Firewire are on the same
>> "bracket" I wonder if there is a discontinuity on a common connection. If
>> it
>> is a board problem I don't want to break it down even though it is under
>> warranty as I will be without it for who knows how long.
>> Barry
>
> If you want to replace the Ethernet with a 10/100 card, those
> are dirt cheap. If you want to buy a 10/100/1000 card, those
> are more expensive (for no good reason). An RMA could well be
> cheaper than buying a 1000BT card.
>
> According to the manual, the stacks are USB,USB,Firewire and
> USB,USB,RJ45. I don't see a sharing there.
>
> While the info is not going to help you, the Ethernet outputs
> are transformer isolated. Generally, there is no DC path to
> ground with respect to an Ethernet output wire. There is a black
> plastic square labelled "Pulse H5007" next to the connector
> stack, and that contains the four transformers used to isolate
> the eight wires. With no DC path, it means two computers can
> have slight differences in their ground potential, without
> causing a problem. If electrical noise is imposed on the cable,
> both wires in a pair "see" the same amount of noise, and the
> noises cancel when they hit the transformer. Each pair is
> differential (signals of opposite polarity), so the receiving
> IC can eliminate any remaining common mode noise.
>
> Pg.3 here shows how the four pairs of wires in the cable are
> transformer isolated. This is what is inside the H5007 plastic
> square, just before the wires go to the RJ-45. On some
> motherboards, this plastic square is actually inside the
> connector stack, but in this case, you have a better quality
> solution, where the square is separate on the motherboard.
> (Better, in the sense that the connector stack thing can
> be lower quality.)
>
> http://www.pulseeng.com/pdf/HC500.pdf
>
> Pg.55 here shows how the transformer is connected to the
> Ethernet chip. This info will only help you if you are
> handy with an ohmmeter. It also shows the pin numbers in
> the RJ-45, and how the pin numbering is not in a particularly
> intuitive order.
>
> http://download.intel.com/design/network/applnots/ap440.pdf
>
> Paul
.
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- P4C800-E DL Lan Disconnects
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- Re: P4C800-E DL Lan Disconnects
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- Re: P4C800-E DL Lan Disconnects
- From: Barry
- Re: P4C800-E DL Lan Disconnects
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