Guided transmission media involves the physical medium for the transmission of information from one place to another. The physical medium guides the information bits and directs them to the path they have to travel in order to reach the desired destination.
Types of Guided Transmission Media
1. Magnetic Media
This is the oldest and most common method for transmitting information from one computer to another. The information to be transmitted is written to the magnetic disk. This magnetic disk is then removed from the source computer and is attached to the destination computer.
Though this is slow as compared to the modern media solutions but yet it is the safest and cost-friendly method.
2. Twisted Pair Cable
The twisted-pair cable provides an online connection for many applications. The twisted-pair cable has two insulated copper wires twisted around each other forming a helical structure.
Although it consists of two copper wires it is used as a single communication line. Where one wire carries the signal other completes the ground circuit. The twisted wired cancels the noise and crosstalk that can affect the signal in the wire.
The twisted-pair cable is easy to install and not even expensive and can be used for both analog and digital signals. The signals of twisted pair cable weaken at a very short distance such as 2 kms and therefore requires amplifiers to strengthen the signal.
3. Coaxial Cable
The coaxial cable has a copper wire at its core. This copper wire is enclosed with an insulating material which is further encased inside a braided mesh made of conducting material. This entire structure is then covered with a plastic sheath.
The coaxial cable is more immune to noise and crosstalk as compared to the twisted pair cable. The coaxial cable was widely used for telephone systems, television cables, and metropolitan area networks. The coaxial cable is expensive and also hard to install.
4. Fibre Optic Cable
The fiber optic cable transfers the information with the speed of light. The fiber optic cable is very thin like human hair and is made of either plastic or glass. The fiber optic cable has three encasing first is core then cladding and the last jacket.
The innermost casing i.e. core has one or more thin fiber strands. Each of these fine strands is enclosed in its own cladding made of plastic or glass. Further, all of these cladded strands are encased inside a jacket.
How the information is transmitted through these strands? At the sender side, the electrical signals carrying the information are converted into light pulses and are transmitted over this fiber optic cable. At the receiver side, these light pulses are received by the light detector and are converted back to the electrical signal.
The fiber optic cable is the fastest means of transmitting the information. The light pulses traveling in the fiber optic cable do not get affected by the electromagnetic waves. It is expensive to install and maintain.
These are the three physical transmission media that guides the information from sender to receiver. The other kind of transmission is unguided transmission media. In unguided transmission media, there are no physical media that can guide the path to the information signals.