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What Is a Rollover Cable?
A network cable with wires that are rolled over and reversed in sequence on each end is called a rollover cable. The first wire connected to the first pin on one end is the same color as the wire attached to the last pin on the opposite end. Also called a Cisco console cable, it is flat and light blue, and has wires colored white-orange, orange, white-green, and blue. The other four wires continue in a sequence and are colored white-blue, green, white-brown, and brown. A rollover cable is often used by programmers to connect devices to network routers and switches, and by technicians to upgrade network systems and conduct troubleshooting and maintenance tasks.
The rollover cable attaches to the console port of a network switch or router. It is different from other cable types in that the wires on one end are reversed in order from the wires on the opposite side. These signal cables are used to connect devices that are similar to one another, while straight through cables, used to connect different components together such as computers to switches, have wires that pass continuously from one end to another. A crossover cable, also known as null modem cable, also has crossing wires and connects routers, hubs, and computers to devices that of the same type and function in the network.
Technical network tasks are generally best served by a rollover cable, as it can support the programming of network devices from a central location. Troubleshooting actions can take place system-wide and all of the hardware components in the network can be upgraded at once. The cable has a very distinguishable look because it is used much differently compared to other cables. It is also the least common type found in the network infrastructure, in comparison to the other cable types that are used for communications between servers, switches, routers and other network components.
A rollover cable can be assembled with common connecting and wiring parts. Twisted pair cables are all that are needed to attach to RJ-45 connectors. The proper configuration of the wires on each end, called the pinout, characterizes a rollover cable. Appropriate markings on the ends of the cable indicate what kind it is, unless different colors of cabling are available to be used. Custom-made cables, not ordered from the manufacturer, should be marked accordingly so they are not confused with other cables that look the same.
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![Cat 5 cable with RJ45 plug.]()
Cat 5 cable with RJ45 plug.
Discussion Comments
@Mammmood - I don’t think that I’ve seen rollover cables. However, I have used null modem cables at work. I work in the utilities industry, and often have to connect my relay test set equipment to my computer to do testing. The computer only has a USB hub, but the test set has a serial port.
So I use a null modem cable to connect the serial port on the test set; one side of the cable has a serial adapter and the other has a USB connector. It works perfectly.
@MrMoody - No, they are not the same and can’t do the same job. The rollover cable connects two “like” devices, not unlike devices. This seems to hold true in most cases.
The only exception I can think of is maybe with Ethernet connecting two computers. I know that you can use Ethernet to connect two computers, and apparently you can use the rollover cable to do the same.
I don’t know what the difference would be. Perhaps there are different connections for the rollover cable, I don’t know.
I guess I don’t get what makes a rollover cable different from an Ethernet or Cat5 cable. I mean, I understand they’re different; I just don’t understand why you need a rollover cable instead of an Ethernet cable. Couldn’t both of them do the same job? I have Ethernet connecting to my cable modem router and my computer.
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