Types of Cables

Transmission Media

( Types of Cables and their Characteristics )

Introduction :-

      Networking involves connection of computers, workstations and peripheral devices. Networking hardware involveves the peripheral devices, interface cards, and other equipments such as cables and wires that are used to establish a network connection. Wire is a single, cylindrical strand of a metal conductor with low resistance to the current flow Cable can be defined as a bunch of wires bound together which may be bare or insulated. 
      
      You can connect these device either using physical transmission medium or using wireless transmission medium. Physical transmission media involves the use of wires and cables.

Characteristics of Cables :-

      Before selecting a cable for Network, you may have to consider various cable characteristics. Every cable has certain advantages and disadvantages. You may have to consider the following criteria before selecting and installing a Network cable:

• Segment length : Every cable has a limitation to carry signals only to a particular distance after which the quality of signals degrades and becomes corrupt. The capacity of the cable to carry signals to a certain distance till the can be regenerated using amplifiers or repeaters is known as the maximum segment of that cable.
• Attenuation : As the signals travel through cables, they lose their strength. This loss of signal strength in a cable is called as attenuation. With more attenuation, the signal strength arriving at destination decreases. As the operating frequency and cable length Increases, Attenuation also increases. Attenuation is measured in Db(Decibels) and expressed as Negative Value as it indicates a loss, for example -12 Db. 
• Bandwidth : It is the amount of digital data that a cable can carry. Each type of cable can carry a certain amount of Information or data over a given period of time. This capacity is measured in terms of Bandwidth. It is measured in terms of Bits and Bytes the cable can carry at a Certain time. It is Important factor while selecting a network cable.
• Cost : Cables comes in different quality. Depending on length, size of the network, you may need to choose the right type of the cable. Copper cables are cheapest form of cable, whereas fiber optic cable are the most expensive. Installation cost of the Copper cable are cheaper as compared to that of fiber optic cables.
• Interference Susceptibility : Each type of cable is susceptible to some interference such as internal or external noise. It depends on the Environment where the cable is to be laid. External noise may consists of Electromagnetic Interference (EMI) or Radio Frequency (RFI). EMI refers to unwanted radiations of noise from external device such as Electric motors or relays. RFI refers to radiations in the radio frequency range interfering with transmission over copper cables. In case of shielded cable, if field is not grounded properly, then it acts as an antenna and picks up such interfering signals. Cable that consists of shielding are less susceptible to interference than unshielded signals. Coaxial Cables and shielded twisted pair cables are less susceptible to interference. Fiber optic cables are the least susceptible to the interference. 
• Cross talk : It is interference caused when magnetic field generated by the current flowing through 1 cable effects electrical currents of other cable. Cable cross talk result in signal distortion which leads towards a network problems. Cross talk can be reduced by twisting and shielding the wire pairs.In twisted pair cable the magnetic field cancel each other to the decrease the cross talk.

Few characteristics can be derived from information written on the cable as shown in the figure :

Types of cables
There are different mediums available for transferring data over the network data transfer the true copper wires by converting them into appropriate electrical signals copper wires are the cheapest mode of copper available there are various types of copper transmission medium available depending on the size of networks and the individual needs the types of cables used for networking coaxial cable twisted pair cables unshielded twisted pair shielded twisted pair fibre optics cable coaxial cable coaxial cables consists of solid copper core surrounded by an insulator or mainly made up of polyvinyl chloride PVC Teflon PVC is a plastic made from chemical Vinay chloride it is surrounded by a Mahesh uae ground wire call the breathing shielding and an outer cover known as Shield the insulator acts as a barrier between the breathing and inner core is the insulator is absent The Shield and the core making contact and causes short circuit the grading protects the cable from Excel in the forest electromagnetic interference and radio frequency interference outer insulation jacket it is made up of polyvinyl chloride copper Mahesh uae cables have a beard I'm have a fallen others have a ground wire copper wire from EMI
Insulation insulation it is non conductor the electric around the career wire it is usually made up of polyethylene or Teflon copper wire or carrier wire it is via conductor at the centre of the cable and is made up of Copper and maybe I the solid or stranded advantages of coaxial cables Secure data transmission protected from crosstalk protection from EMI disadvantages of coaxial cable to install types of coaxial cable rg58 cable rg58 cable is mainly used in network devices or removed easy to add or remove devices from network using 58 cable coaxial cables specifications