I need to make a ethernet crossover cable to connect two devices together. Anyone know the process to make one from scratch?
Check out this tutorial. Here are some images from it for context:
Note that the TX (transmitter) pins are connected to corresponding RX (receiver) pins, plus to plus and minus to minus. And that you must use a crossover cable to connect units with identical interfaces. If you use a straight-through cable, one of the two units must, in effect, perform the cross-over function.
Note that pins 4, 5, 7, and 8 and the blue and brown pairs are not used in either standard. Quite contrary to what you may read elsewhere, these pins and wires are not used or required to implement 100BASE-TX duplexing--they are just plain wasted.
OW O GW B BW G BrW Br
GW G OW B BW O BrW Br
In other words swap the orange/white with the green/white and the orange with the green on one end of the cable. Compare against a standard cable to make sure you have it right. Make sure you only unwravel as much of the cable ends as you need. Too much will cause crosstalk.
One time I made so many CAT5 patch cables my fingers started to bleed.