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Covingtonas
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Wed Mar 09, 2005 5:27 pm

Data through PIN1 and PIN2. How?

Tue Mar 21, 2006 6:29 pm

PC NIC sends data through one pair, pin 1 and pin 2, there is two wires. How it does that, what information goes to pin1 and what goes to pin2? How it place information on these two wires? There is everything looks simple when there is one wire, but how it works with two wires, especially on another side cable, who receives information, how NIC combine information from two wires?

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Grand Styolz
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Wed Mar 22, 2006 12:49 am

Basically, its transmit and receive. Everything is sent via Bits or Binary through the wire (signal pulses). A standard 10-BaseT or 100-BaseTX cable is pretty wasteful if you really look into it. I remember back in freshmen year, we had to do a report on how Ethernet worked and how they are used. From what I can remember, I believe the first and second PIN on a standard strait-through Cat5e cable is for transmission and the third and sixth PIN are for receiving data. That’s about it! I think everything else isn't really used for any transmission. I could be wrong but I think the rest of the PINs maybe used for signal cancellation for concentrated transmission…being able to transmit data 100m and such..but I’m no Electrical Engineer so yea :o

geko29
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Wed Mar 22, 2006 7:10 am

100Base-TX only uses 4 wires, two of which are grounds, so there's really just one transmit and one receive. 100Base-T4 (which nobody supports) used to use all 8 wires (2 transmit, 2 receive, 4 ground), and Gigabit over copper (1000Base-TX) uses all 8 wires in both directions--simultaneously. For this reason, traditional crossover cables don't work for Gigabit, because only the wires used in 100BT are crossed, so it's effectively half a crossover and half a straight through cable as far as GigE is concerned.

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jdsilva
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Fri Mar 24, 2006 11:31 pm

Damn Geko, you seem to always have a good answer for any question I could answer :P

In the effort to make myself feel important I'm going to elaborate a bit on what Geko said...

What you're asking enters the realm of electrical theory. A ground wires provides a baseline in which the positive wire is measured against. The "value" for ground will vary depending on many variables, so is is included to provied a "baseline" for that particular connection, be it a power cord, ethernet cable, or anything else.

So that means the "value" of a ground wire at building A may not match the value of a ground wire at building B. However, as long as you can measure to a baseline, you can know what any given value on the + wire equals. This is what a ground is.

j


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