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Commonly confused · Networking Fundamentals

Straight-Through vs Crossover Cable: What's the Difference?

A straight-through cable uses the same wiring standard on both ends and connects unlike devices, such as a PC to a switch. A crossover cable uses T568A on one end and T568B on the other, swapping transmit and receive pairs to connect like devices directly.

Straight-Through Cable

Full definition
vs

Crossover Cable

Full definition
Straight-Through CableCrossover Cable
WiringT568B to T568B (or A to A)T568A to T568B
Pairs swappedNonePins 1-2 and 3-6 swapped
ConnectsUnlike devices: PC to switch, router to switchLike devices: switch to switch, PC to PC, router to router, PC to router
Modern relevanceStill the default patch cableMostly unnecessary thanks to Auto-MDIX
Not to be confused withRollover (console) cableRollover cable, which reverses all 8 pins
Remember it

Same ends, different devices; different ends, same devices.

Exam tip

Questions ask which cable connects two given devices, assuming no Auto-MDIX. Remember a PC and a router are both MDI devices, so they need a crossover, and do not confuse a crossover cable with a rollover (console) cable.

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