Take the 2-minute tour ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

If not please explain the difference in terms of usage

share|improve this question

2 Answers 2

up vote 13 down vote accepted

Twisted Pair refers to the cable itself. Two conductors inside the cable are wound round each other to cancel out electromagnetic interference. A Twisted Pair cable could carry all kinds of signals.

A Crossover Cable refers to how the contacts in the cable connectors are connected to the wires at each end of the cable. In this case the connectors are connected asymmetrically so you can do things like connect the input of one device to the output of another (which a "straight-through" cable would not normally do). A common case is an Ethernet Crossover Cable which allows you to connect two ethernet ports on two systems directly together without using a hub or switch; this works because some pin assignments are swapped from one end of the cable to the other.

Ethernet cables are usually UTP so a crossover cable will be a twisted pair cable, but so would an ordinary ("straight-through") ethernet cable. The two things are not related directly.

share|improve this answer
    
so this means that straight through cables cannot be used to connect two devices? –  user39966 Oct 28 '10 at 12:03
1  
Sometimes they can be, it depends on the ethernet port. Some ports will automatically configure themselves to work appropriately as part of the auto-negotiation process. homepage.ntlworld.com/robin.d.h.walker/cmtips/… –  Dave Webb Oct 28 '10 at 12:06
    
This autonegotiation is referred to as Auto-MDIX. –  Dennis Williamson Oct 29 '10 at 3:24
    
user39966: It depends on what the devices ARE. Historically you would use a straight-through (s-t) cable to connect a computer to a port on a switch or a hub, and a x-over cable to connect computer to computer. To connect one port on the switch to a port on an "upstream" switch you would either use a x-over, or put one of the ports in question into crossover (MDI-X) mode and use a s-t cable. Older switches and hubs had one port with a physical switch for this purpose. Most modern switches (and some computer NICs too) implement auto-MDI-X so they will automatically take care of this. –  Jamie Hanrahan Sep 15 at 21:42

Twisted pair is the type of cable, crossover is a type of way twisted pair can be wired up at the jacks.

Crossover cables are made of twisted pair cable, so are straight-through cables.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.