Crossover Cables – Understanding Their Function and Use

Your thought process is based on faulty assumptions. By splicing 1 to 3 and 2 to 6 (which is what you have done), this does not put them in the same collision domain. Nor does this cause the devices to autonegotiate into half-duplex mode. Connect only one side of your main cable to one device and what you have now created is basically a "loopback."

Look at a hubbed 10BaseT or 100BaseTX environment. While they are in the same collision domain, they still have separate TX and RX pairs, they don't transmit in both directions on the same pair.

The reason for the collision domain is that a hub is ultimately a repeating device, which takes a signal in one port and repeats it out all other ports. If it receives traffic on two ports and repeats it out the other ports, the signal that is repeated will be a "collision" of the two signals creating an unusable signal. Thus the need for CSMA/CD and half-duplex operation.

By having three devices all spliced together in this fashion, you have merely created an environment that won't work. If you want to do this, simply put a hub between your two devices and connect a "listening" device to it. No need for a tap.

First off, the manufacturer may claim Category-6, but the UTP standard says that patch cords cannot exceed 5 meters, and this claims 100'.

It is highly unlikely that this cable can actually pass the Category-6 suite for patch cords in all the other tests in the suite (it will fail for length). If you happen to get one, get it tested on a high-end tester that can test the Category-6 suite.

At speeds up to 1 Gb, Category-5E and Category-6 will both either work at the full 1 Gb, or they are not properly installed. A cable system only gets the rating of the lowest rated component (horizontal cable, terminations, patch panels, patch cords, etc.) in the system. Buying Category-6 anything to add to a lower rated system is a waste of money.