I want to be able to use my ethernet card and detect signals from it using LED lights, and way later on in more sophisticated SBC circuits.

I researched, and I noticed that four pins are marked TX+, TX-, RX+, and RX-.

Does it work if I leave TX- floating, RX- floating, and connecting TX+ to my input source (which for now is a button tied to +5V), and connecting RX+ to the anode of an LED and a resistor in series, and grounding the other end of the resistor? or do I have to do an analog to digital conversion?

 

"TX" means "transmit" and "RX" means "receive." The + and - indicate correct polarity. Your RX will not source or sink current. Your TX will provide only a few milliAmps peak - a couple dozen a the very most. Your card will be pulsing the output, not sending a steady "on."

See also: http://en.wikipedia.org/wiki/Ethernet_physical_layer

 

When you say that it doesn't produce a steady "ON", do you mean that I am to use the RX+ and RX- as if it were an AC signal?

all I need is a simple circuit that can convert these signals to digital signals. USB has digital signals, but I want to use ethernet because it has far greater compatibility with more systems.

Serial can provide digital output but at higher voltages.

 

When you say that it doesn't produce a steady "ON", do you mean that I am to use the RX+ and RX- as if it were an AC signal?

No. I mean there is a pulse train. That's why I said "pulsing." You did read the link I provided?

all I need is a simple circuit that can convert these signals to digital signals.

They are already digital signals. You did read the link I provided?

Here's more information: http://books.google.com/books?id=Oh...ig=BXlAf_TQM_Wey7gB7DqR0ippLfY&hl=en#PPA85,M1