Straight Cable and Cross-over Cable

Common Ethernet network cables are straight and crossover cable. This Ethernet network cable is made of 4 pair high performance cable that consists twisted pair conductors that used for data transmission. Both end of cable is called RJ45 connector.

The cable can be categorized as Cat 5, Cat 5e, Cat 6 UTP cable. Cat 5 UTP cable can support 10/100 Mbps Ethernet network, whereas Cat 5e and Cat 6 UTP cable can support Ethernet network running at 10/100/1000 Mbps. You might heard about Cat 3 UTP cable, it's not popular anymore since it can only support 10 Mbps Ethernet network.Straight and crossover cable can be Cat3, Cat 5, Cat 5e or Cat 6 UTP cable, the only difference is each type will have different wire arrangement in the cable for serving different purposes.
Straight CableYou usually use straight cable to connect different type of devices. This type of cable will be used most of the time and can be used to:

1) Connect a computer to a switch/hub's normal port. 

2) Connect a computer to a cable/DSL modem's LAN port.  

3) Connect a router's WAN port to a cable/DSL modem's LAN port.  

4) Connect a router's LAN port to a switch/hub's uplink port. (normally used for expanding network)  

5) Connect 2 switches/hubs with one of the switch/hub using an uplink port and the other one using normal port.

 In straight cable connectivity is like as followsRJ451 Connected to RJ452                               

Pin1------------------------------------- Pin1    

Pin2------------------------------------- Pin2 

Pin3------------------------------------- Pin3 

Pin4------------------------------------- Pin4 

Pin5------------------------------------- Pin5  

Pin6------------------------------------- Pin6  

Pin7------------------------------------- Pin7 

Pin8------------------------------------- Pin8 

Crossover Cable Sometimes you will use crossover cable, it's usually used to connect same type of devices. A crossover cable can be used to:

1) Connect 2 computers directly.  

2) Connect a router's LAN port to a switch/hub's normal port. (normally used for expanding network) 

3) Connect 2 switches/hubs by using normal port in both switches/hubs.

 RJ451 Connected to RJ452  

Pin1------------------------------------- Pin3

Pin2------------------------------------- Pin6

Pin3------------------------------------- Pin1

Pin4------------------------------------- Pin4

Pin5------------------------------------- Pin5

Pin6------------------------------------- Pin2

Pin7------------------------------------- Pin7

Pin8------------------------------------- Pin8