Straight through cable vs Crossover cable

[Honorata]

Hi,

How can you can connect PC to switch with straight or cross-over cable, what is the difference between these two ways, Straight through cable vs Crossover cable? Why are their two types of cables? What do they do?

[Hoobastank]

Straight through cable means, the cable wire goes through straight, transmission wires over to the reception end. You use a crossover cable when you are connecting two PCs together directly (NIC to NIC). To connect Router to Router and Computer to Computer need Crossover and the usually the rest need Straight-through cable.

[SergioSantos]

You use a straight-through cable when there is a hub, switch or router between the two or more PCs (NIC-Hub/Switch/Router-NIC). The is no difference in speed, it's just a method of communicating. It depends on the hardware, all you need is either a free LPT or com port on each computer and a cable plugged into these ports between each computer.

[Rasdasa]

The simple answer is a crossover cable is used when you are connecting two PCs together directly (NIC to NIC), to connect two computers to each other, you use a crossover cable. When two crossover cables are connected in series, as when going through a patch panel, the result would no longer be a crossover.

[Tylon Foxx]

A crossover cable swaps the Transmit and Recieve lines in one end so that the computers can communicate.

If you connected a straigt-through cable directly between two computers, there would be a clash of data because they both use the same wires for transmission or recieving.

Take a good look at the picture above, it shows what I mean. In a straight through cable, both ends are arranged as end A, while in a crossover cable, one end is arranged as end B.
This can also help if you want to make a cable yourself

In order to connect two computers with crossover cables, you must set their IP addresses to be in sequential order. For example:
Computer 1: 192.168.1.1
Computer 2: 192.168.1.2

This requirements also exists in some hubs.

Connecting computers through a switch does not have this requirement as it resolves the transmitter and recievers through the MAC address, which is a unique address burned directly into the NIC.