There is no doubt that the straight through cable has a high performance in the applications where two different types of devices need to be connected, for instance, the connection between a computer and a network switch or hub. However, if two devices that have the same type are required to be connected, the straight through cable is no longer recommended. Then which kind of cable should you choose? The answer is the crossover cable, which is designed to connect two similar devices together directly. Are you familiar with this kind of Ethernet patch cable? Let’s explore the basic information of the crossover cable and when and where it should be used.
The crossover cable is also known as the crossed cable, supporting the temporary host-to-host networking in situations where an intermediate device like a network router is not present. Although the crossover cable is a common type of Ethernet patch cable like the straight through cable, it is not so popularly applied as the the latter one. Meanwhile, its function is also unlike that of the straight through cable, usually offering the connection between two similar devices as the simplest and fastest way. Furthermore, it is capable of reversing the transmit and receive signals via the reversed color-coded wires inside the cable.
To better understand the internal reversed color-coded wires of the crossover cable, you can learn it from the RI45 jacks at each side of the cable, as shown in the following figure. From the figure, you can the wire arrangement of the straight through cable can be TIA/EIA 568A or T568B standard with an identical sequence of colored wires on each side of the cable, while the wire arrangement in the crossover cable is reserved like TIA/EIA 568A or T568B crossed standard, for instance, counting from left to right, the first and third wires crossed, the second and sixth wires crossed, the third and first wires crossed, etc.
Generally, if you want to deploy a Ethernet network at home with multiple PCs, you should connect all the computers to a central router first. Then the router can take all the bits being sent out by the computers and relay them onto the other devices on the network. Is this way of Ethernet network deployment complicated? Can the crossover cable make the deployment easier? Is there any other advantage by using the crossover cable?
In fact, you can use the crossover cable to connect two computers directly, without the help of the router. Using the crossover cable to deploy your network can simply reverse some of the pins so that the output on one computer is being sent to the input of another, instead of choosing the traditional deployment. Except that, expanding your network by connecting another network switch is another advantage of using the crossover cable, thereby more ports can be provided to you. In all, it’s always convenient to own a length of crossover cable for easy Ethernet network deployment.
In the 1990s and 2000s, the popular Ethernet network deployment cannot support the direct cable connection between the hosts. Under the situation, the crossover cable was published to solve the issue that was widely used by Information Technology (IT) at that time. But now most of the network devices have the ability to automatically detect when a port should be run in cross-over mode, or give you a physical switch that you can use to enable the mode. Considering that, do you still need a crossover cable?
Actually, you should use the crossover cable for your network if you are working with the old hardware. Moreover, if quick connection between two computers in a network-less environment is required, you are also strongly suggested to choose the crossover cable.
The crossover cable is one common type of Ethernet patch cable, serving for the direct connection between two devices with the same type. As its function is clearly different from the straight through cable, can you tell the two types of Ethernet patch cables? In fact, most of the crossover cables are generally red in color and stamped with its name "crossover" on the packaging and wire casing. Besides, if there is no mark to distinguish them, you can simply check the wire colors inside the RJ45 jack at both side of the cable. When the wire colors at both side are in the same order, it is a straight through cable; Otherwise, it should be a crossover cable.