Crossover cables are a type of ethernet cable that is used to connect two computers together directly. It can connect other devices as well, provided both are of the same type – for example, two switches, but not a computer and a switch.
For modern computers (ones from the year 2000 and on), crossover cables aren’t really needed anymore. Standard Ethernet cables work just as well thanks to the implementation of newer standards and protocols like the MDI-X feature.
This helped streamline the sending and receiving of signals from either of the two connected devices, and it automated much of the process of the connection. It also helped avoid signalling conflicts, which were an issue in early connections.
Though not obsolete, crossover cables are no longer as common as they used to be, and in almost all cases, a standard Ethernet cable can be used for the same purpose.
What makes crossover cables different from normal Ethernet cables?
As both are used to establish connections, you may struggle to tell them apart. They are very similar, with one key difference. Although both cables feature the same (multi-coloured) wires on the inside, standard cables have the same order of wires on both ends.
The wires are arranged in the pattern 1-2-3-4-5-6.
In a crossover cable, four wires are crossed, meaning that one end of the cable has a different order and setup of wires.
In a crossover, the wire arrangement looks more like this: 3-6-1-4-5-2.
Externally, the two can look much the same – they both have the exact same connectors. It is however fairly common for these cables to be specifically stamped with the word “crossover” either on the cable or connector itself, or at least the packaging. This type of cable is also often red, while standard Ethernet cables tend to be white or black.
What are crossover cables used for?
Crossover cables are still needed in one specific scenario – to connect devices that aren’t outfitted with Gigabit Ethernet functionality. This is a high-quality, high-speed standard found in most but not all modern devices that support Ethernet.
In the case of two devices using older and slower standards, a crossover cable is needed to network them together.
What are crossover cables NOT used for?
Crossover cables should not be used to attempt an ethernet connection between two dissimilar devices, and they cannot substitute standard Ethernet cables for connections to a network.
In other words, plugging a crossover cable between a computer and a router simply won’t work – it likely won’t let the connection be established. Use a normal Ethernet cable for this purpose.