Wiring Straight and Crossover Ethernet Cables

So how do you know when to use a straight-through cable and when to use a crossover? That’s simple. You always use a straight cable when you’re connecting ports of different types. When you’re connecting devices of the same type, you always need a crossover cable. The table below outlines different scenarios and the cables required. Hub and switch ports are wired in the same way, as are PC and router ports.

Cable types used to connect devices:

Connection Cable Required
PC to Hub = Straight
PC to Switch = Straight
Router to Switch = Straight
Router to PC = Crossover
Hub to Hub = Crossover
Hub to Switch = Crossover
Switch to Switch = Crossover

Note from the previous figure that the crossover cable actually ensures that the transmit pins from one system connect to the receive pins of the other device when two devices have identical ports.

Author: Dan DiNicolo

Dan DiNicolo is a freelance author, consultant, trainer, and the managing editor of 2000Trainers.com. He is the author of the CCNA Study Guide found on this site, as well as many books including the PC Magazine titles Windows XP Security Solutions and Windows Vista Security Solutions. Click here to contact Dan.