Communication Medium



Introduction to Network Cables

Communication is the process of transferring signals from one point to anotfher and there must be some medium to transfer those signals. In computer networking and especially in the local area networking, there are certain communication mediums. This section provides the basic overview of the network cables, lan communication system and other transmission mediums in LAN and WAN. Today many standardized communication cables and communication devices are in use the according to the needs of a computer network. LAN data communication systems there are different types of cables are used. 

The most common types of the LAN cables are the Ethernet UTP/STP cables. An Ethernet cable is a twisted pair cable that is consist of eight cables that are paired together to make four pairs.



A RJ-45 connector is joined with both ends of the cables and one end of the connector is connected with the LAN card of the computer and the other end of the cable is connected with the hub or switch. Cable testers are used to test the performance of each cable. The preferable cable in the Ethernet networking is the 100baseT, which provides the best communication speed. UTP/STP is a standardize cable in which data is transferred which provides the transmission speed of 10/100 mbps.

The most commonly used cable in the star topology is the UTP/STP cable. UTP/STP cables are same in functionality only a slight difference is that an extra protective silver coated layer surrounds the cable. UPT/STP cables are further divided into straight over and cross over cables. The most common use of the UTP/STP cables is the serial transmission, Ethernet, ISDN, fixed and modular interfaces in the WAN networking. Straight over cables are used to connect the computer with the hub or switch and a cross over cable is used to connect the hub with a hub or with a switch.

In the cross over cables, first and third cables and crossed with the second and sixth cable. There is another type of the cable which is coaxial cable that is used in the bus topology. All the computers in the bus topology are connected with the same coaxial cable thus forms the shape of a linear bus. If any portion of the cable is damaged, then the whole cable becomes useless. Another common use of the coaxial cable is in the cable TV network. An outer protective covering provides insulation between the inner copper wire and the outer twisted metal field.

Coaxial cables are also used in the microwave frequencies but there not as popular as other cables. The most advanced form of the communication cables is the fiber optic cable. Fiber optic cable is a very expensive cable that is composed of a number of thin fibers that are covered with the insulating covering. Data is traveled at the speed of light in those fibers. Today FTTH (fiber to home installation) is becoming very popular and FTTH is giving the speed of 100 mbps to the home users. According to the current trend of the home networking and bandwidth requirements, fiber optic cable will replace all the other cables. Once the price of the fiber optic cables is reduced it will be more in demand for every home and office network.

Fiber optic cables are designed for high speed data communication for the corporate offices and ISPs, backbones and in the telecommunication industry. Fiber optic cable acts as a backbone cable when it connects two ISPs with each other. In the internet communication, there is a major role of the fiber optic cable, which acts as a backbone. There is another type of cable which is called Roll over cable that is used connect the consoles of the Cisco Routers and switches and RJ-45 connectors are used to at the both ends of the roll over cables. Today many networks are shifting to the other types of the networks such as radio transmission, infrared; Bluetooth and these all are the type of the wireless networking. Wireless networking has its own infrastructure where access points, routers, switches, wireless network connections and wireless network cards are used. The only major difference in the wireless and wired networking is the usage of the cables, which plays the role as a transmission medium.