What Is the Crossover Cable?

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 Overview

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.

The Crossover Cable Advantages

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.

The Crossover Cable Applications

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.

Conclusion

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.

Guides for Selecting Ethernet Patch Cable

Ethernet patch cable, the copper-based patch cable, may perform not so good as fiber optic patch cable in deploying Ethernet network, but it is still very commonly used in many applications, such as PCs, routers, and switches, as an accessible, popular and low-cost solution. At present, there are various types of Ethernet patch cables available in the market that may not be very easy to classify if you are not familiar with them. In this paper, it will introduce four widely used types of Ethernet patch cables according to different standards that you can take as reference to select the most suitable one for deploying your network.

STP and UTP Cable

There are two types of Ethernet patch cables according to whether the cable is shielded or not, known as shielded twisted pair (STP) cable and unshielded twisted pair (UTP) cable. As for the structure of these two types of copper cables, here offers their differences in the following figure for your reference. Besides, it is worth mentioning that shielding is one of the common methods to decrease or avoid EMI, aiming at protecting the whole cabling system.

As for the STP cable, it is always made up of even wires that are shielded by a metallic substance. Just taking an eight-strand cable as an example, all the four pairs of the wires are twisted, shielded and then wrapped in another metallic protector, as shown in the above figure. Through shielding, cancellation and wire twisting, the STP cable can be well protected from interference. It is highly recommended to use the STP cable in industrial settings with high amounts of electromagnetic interference (EMI), such as factories with large electronic equipment. However, there is an important issue that should be paid attention to if you choose the STP cable to deploy Ethernet network. After installation, you should check and ensure that it is installed and grounded properly, or the shielded Ethernet cable will act as an antenna and pick up signals when your network runs.

As for the UTP cable, it is easy to learn that it is designed without shielding. Compared to the STP cable, it is much simpler to install and less expensive due to its unshielded property. But without shielding, how to reduce or avoid interference when using the UTP cable? Or this kind of cable has no ability to decrease the interference? In fact, the UTP cable depends on the twisted pair inside the cable to cancel EMI. Meanwhile, it does not require as much maintenance but can transmit data as fast as the STP cable, since it don’t rely on the outer shielding. As for its application, it is always used in domestic and office Ethernet connections, and in any area where there is not a high degree of EMI.

Solid and Stranded Cable

The solid and stranded cable with different features are designed for various applications. Knowing their features and acquiring when and where they should be used will be helpful for you to improve networking performance and efficiency when designing your network. The following will introduce the structure and advantages of these two kinds of copper cables, then you can have a good knowledge of which should be selected and used for deploying your network.

As shown in the above figure, the solid cable consists of a single, solid conducting wire, insulated with non-conductive materials. With the feature of large-diameter wire, it is physically stronger than the stranded cable and capable of remaining stable over a wider range of frequencies, providing superior electrical characteristics and supporting long transmission with high data rates. Meanwhile, it has a lower DC resistance and a lower susceptibility to high frequency effects than the stranded cable due to its large-diameter wire. All these advantages make the solid cable better suited to the new and emerging high-speed Ethernet applications. However, the large diameter feature of solid cable brings a serious disadvantage at the same time. It could be easy to be break for lack of flexibility as they cannot be flexed or bent for many times without breaking. Hence, the solid cable is an ideal solution for horizontal cabling applications with long transmission distance.

Greatly different from the solid cable, the stranded cable is composed of a bundle of twisted, small gauge wire strands. Its diameter of each individual wire strand is much smaller than that of the solid cable, making it much more flexible and hard to break even if it is repeatedly flexed or bent. Although the stranded cable is not so reliable as solid cables for long distance transmission, it features high flexibility that makes itself easy to constantly plugged, unplugged, bent or installed without harm or risk of performance failure, as an optimal choice for short distance transmission.

Conclusion

From this paper, we can learn four widely used types of Ethernet patch cables with different features that are suitable for different applications. The STP cable is always applied in industrial settings with high amounts of EMI, while the UTP cable is more commonly used in domestic and office Ethernet connections, and in any area where there is not a high degree of EMI. If you want to establish a horizontal, long-distance network with high reliability, the solid cable is strongly recommended. But if long distance is unneeded, you are suggested to use the stranded cable which is a good choice for short distance transmission with high flexibility. In short, choosing the most suitable Ethernet patch cable to deploy your network that can greatly improve your network performance and extend life span of your equipment.