In data communication terminology, a transmission medium is a physical path between the transmitter and the receiver i.e. it is the channel through which data is sent from one place to another. Transmission Media is broadly classified into the following types:
It is also referred to as Wired or Bounded transmission media. Signals being transmitted are directed and confined in a narrow pathway by using physical links.
There are 3 major types of Guided Media:
1. Twisted Pair Cable
It consists of 2 separately insulated conductor wires wound about each other. Generally, several such pairs are bundled together in a protective sheath. They are the most widely used Transmission Media. Twisted Pair is of two types:
(i) Unshielded Twisted Pair (UTP)
UTP consists of two insulated copper wires twisted around one another. This type of cable has the ability to block interference and does not depend on a physical shield for this purpose. It is used for telephonic applications.
Shielded Twisted Pair (STP)
This type of cable consists of a special jacket (a copper braid covering or a foil shield) to block external interference. It is used in fast-data-rate Ethernet and in voice and data channels of telephone lines.
(ii) Coaxial Cable
It has an outer plastic covering containing an insulation layer made of PVC or Teflon and 2 parallel conductors each having a separate insulated protection cover. The coaxial cable transmits information in two modes: Baseband mode(dedicated cable bandwidth) and Broadband mode(cable bandwidth is split into separate ranges). Cable TVs and analog television networks widely use Coaxial cables.
(iii) Optical Fiber Cable
Stripline is a transverse electromagnetic (TEM) transmission line medium invented by Robert M. Barrett of the Air Force Cambridge Research Centre in the 1950s. Stripline is the earliest form of the planar transmission line. It uses a conducting material to transmit high-frequency waves it is also called a waveguide. This conducting material is sandwiched between two layers of the ground plane which are usually shorted to provide EMI immunity.
In this, the conducting material is separated from the ground plane by a layer of dielectric.
It is also referred to as Wireless or Unbounded transmission media. No physical medium is required for the transmission of electromagnetic signals.
There are 3 types of Signals transmitted through unguided media:
(i) Radio waves: These are easy to generate and can penetrate through buildings. The sending and receiving antennas need not be aligned.
(ii) Microwaves: It is a line of sight transmission i.e. the sending and receiving antennas need to be properly aligned with each other. The distance covered by the signal is directly proportional to the height of the antenna.
(iii) Infrared: Infrared waves are used for very short distance communication. They cannot penetrate through obstacles. This prevents interference between systems.
|1. What are the different types of transmission media used in computer science engineering?|
|2. What are the advantages of using wired transmission media?|
|3. What are the disadvantages of using wireless transmission media?|
|4. What are the advantages of using satellite transmission media?|
|5. What are the different types of cables used in wired transmission media?|
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