Ethernet Crossover Cable, when should I use one?

Ethernet crossover cables are most often used in home networks when connecting two ethernet computers without a hub. An Ethernet crossover cable has it's send and receive wires crossed.  When using a hub or switch, this is automatically done for you.

Unfortunately some devices like cable and dsl modems have their actual ethernet plugs reversed.  This is to allow people to hook up a cable modem to a computer without a special crossover cable.  When adding a hub into the mix, the issue can get confusing.

Most modern hubs and switches have what is called an uplink port on them.  This is the same kind of 'reversed' port that is on a cable or dsl modem.

This may sound like a confusing issue, but here are some network diagrams that will show when to use a normal ethernet cable and when to use a crossover cable.

No Crossover cable needed	Crossover cable IS needed

Note: One port on your hub will usually be 'shared' with the uplink port.  Either the uplink port OR the standard port can be used, no both.

Check toward the bottom of this page for great prices on crossover and standard ethernet cables.

Ethernet Crossover Cable, when should I use one?