These ethernet crossover cables are used to connect two devices together directly. They are most often used to connect two devices of the same type, for example two computers (by means of network interface controllers) or two switches to one another. They are wired in such a way to allow communication directly between the two devices. Using a crossover cable it is possible to share files between two computers or similar tasks.
These Crossover cables are not your average patch cables, they will only work for specific applications; they are NOT commonly used in home network setups.