Straight-Through and Cross-Over cables
CAT 5 UTP cabling usually uses only four wires when sending and receiving information on the network. The four wires, which are used, are wires 1, 2, 3, and 6. When you configure the wire for the same pin at either end of the cable, this is known as a straight-through cable.
If we use want to connect two computers together with a straight-through cable, we can see that, the transmit pins will be connected to transmit pins and receive pins will be connected to receive pins. We will not be able to connect two computers or two hubs together using straight through cables.