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What Is a Crossover Cable?

When you need to connect two network devices of the same type

By Bradley Mitchell Bradley Mitchell Writer Massachusetts Institute of Technology University of Illinois An MIT graduate who brings years of technical experience to articles on SEO, computers, and wireless networking. lifewire's editorial guidelines Updated on September 21, 2021 Reviewed by Ryan Perian Reviewed by Ryan Perian Western Governors University Ryan Perian is a certified IT specialist who holds numerous IT certifications and has 12+ years' experience working in the IT industry support and management positions. lifewire's editorial guidelines Tweet Share Email Tweet Share Email Home Networking The Wireless Connection Routers & Firewalls Network Hubs ISP Broadband Ethernet Installing & Upgrading Wi-Fi & Wireless An Ethernet crossover cable, also known as a crossed cable, connects two Ethernet network devices. These cables support temporary host-to-host networking in situations where an intermediate device, such as a network router, is not present. Crossover cables look almost identical to ordinary, straight-through (or patch) Ethernet cables, but the internal wiring structures are different.

What Is a Crossover Cable

An ordinary patch cable connects different types of devices, for example, a computer and a network switch. A crossover cable connects two devices of the same type. You can wire the ends of a patch cable in any way as long as both ends are identical. Compared to straight-through Ethernet cables, the internal wiring of a crossover cable reverses the transmit and receive signals. You can see the reversed color-coded wires through the RJ-45 connectors at each end of the cable: Standard cables have an identical sequence of colored wires on each end.Crossover cables have the first and third wires (counting from left to right) crossed and the second and sixth. Tom Grill / Photographer's Choice RF / Getty Images A good Ethernet crossover cable has special markings that distinguish it from straight-through cables. Many are red and have "crossover" stamped on the packaging and wire casing.

Do You Need a Crossover Cable

Information technology (IT) professionals used crossover cables often in the 1990s and 2000s; the popular forms of Ethernet did not support direct cable connections between hosts. Both the original and Fast Ethernet standards were designed to use specific wires to transmit and receive signals. These standards required the two endpoints to communicate through an intermediate device to avoid conflicts caused by using the same wires for both transmit and receive. A feature of Ethernet called MDI-X provides the necessary auto-detection support to prevent these signal conflicts. It allows the Ethernet interface to automatically determine which signaling convention the device on the other end of the cable uses ​and negotiates the transmit and receive wires accordingly. Only one end of a connection needs to support auto-detection for this feature to work. Most home broadband routers (even older models) incorporated MDI-X support on their Ethernet interfaces. Gigabit Ethernet also adopted MDI-X as a standard. Crossover cables are needed only when connecting two Ethernet client devices, neither of which is configured for Gigabit Ethernet. Modern Ethernet devices automatically detect the use of crossover cables and work with them seamlessly.

How to Use Ethernet Crossover Cables

You should only use crossover cables for direct network connections. Attempting to connect a computer to an old router or network switch with a crossover cable instead of a normal cable can prevent the link from functioning. You can purchase these cables through electronics outlets. Hobbyists and IT professionals often prefer to make their own crossover cables instead. To convert a straight-through cable to a crossover cable, remove the connector and reattach the wires with the appropriate transmit and receive wires crossed. Was this page helpful? Thanks for letting us know! Get the Latest Tech News Delivered Every Day Subscribe Tell us why! Other Not enough details Hard to understand Submit More from Lifewire Ethernet Cables, How They Work and How to Choose the Right One Can I Move My Modem to Another Room? How to Connect Two Home Computers Through a Network Introduction to Network Cables and Network Cable Types Patch Cable Types and Uses What Is a PATA Cable or Connector? How to Connect Two Routers on a Home Network How to Reseat Internal Data and Power Cables What Is a Switch? Computer Networking What Is an Ethernet Port? What Is a Hub in a Computer Network? How to Fix Common Car Amp Problems How to Set Up a Router How to Fix Network Cable Unplugged Errors in Windows What Is an Uplink Port in Computer Networking? Wired vs. Wireless Networking Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up Newsletter Sign Up By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. Cookies Settings Accept All Cookies