The key difference between Guided Media and Unguided Media is that in guided media, the signals travel through a physical medium while in unguided media, the signals travel through the air.
In data communication, the transmitter sends the signals, and the receiver receives them. The transmission media is the path between the transmitter and the receiver. And, there are two types of transmission media. They are the guided media and unguided media.
CONTENTS
1. Overview and Key Difference
2. What is Guided Media
3. What is Unguided Media
4. Side by Side Comparison – Guided Media and Unguided Media in Tabular Form
5. Summary
What is Guided Media?
In guided media, the signals travel through a solid medium. The transmission capacity depends on factors like length, medium, etc. Few examples of guided media are the twisted pair, coaxial cable, and optical fiber. Twisted pair cable transmits both analog and digital signals. It consists of two insulated copper wires arranged in a spiral pattern. Twisting helps to decrease the interference between the adjacent pairs of a cable. Moreover, there are two types of twisted pairs; they are the shielded twisted pair (STP) and the unshielded twisted pair (UDP).
Figure 01: Twisted Pair Cables
The coaxial cable is a better communication method as it requires a low cost. A baseband coaxial cable allows baseband communication and uses digital signalling. The copper wire has an in insulated covering and a braided outer conductor. Further, a protective plastic covering surrounds all these. A broadband coaxial cable allows analogue transmission. It uses analog signalling. One popular coaxial cable is the cable tv for TV signal distribution. Usually, a coaxial cable carries high-frequency signals than the twisted pair cables.
Figure 02: Coaxial Cable
Fiber optics transmit signals in the form of light. It sends them through an extremely thin medium made up of silicon or glass. The core of this cable is the innermost section, and it consists of a single solid dielectric cylinder surrounded by another solid electric cladding. The reflexive index of the cladding is less than the reflexive index of the core. As a result of that, the light propagates through multiple total internal reflections.
Figure 03: Fiber Optics
On the positive side, the optical fiber reduces noise, attenuation and provides higher bandwidth than the twisted cable and coaxial cable. Although it has many positives, there are some drawbacks too. That is, the cost of installation and maintenance of optical fiber is expensive.
What is Unguided Media?
The wireless communication utilizes the unguided media in which the signals travel through the air. The method is desirable in places where it is hard to run a physical cable between the two endpoints. Radio waves, microwaves, and infrared waves are few examples of unguided media.
Figure 04: Microwave Transmission
Radio waves are low-frequency signals and propagate in all directions. Therefore, it is not necessary to align the sending and receiving antennas. However, it is suitable for long distance broadcasting.
On the other hand, the microwave has a higher frequency than radio waves. But, the distance a signal can travel depends on the height of the antenna. Furthermore, the microwave requires line of sight transmission. Cellular phones, satellite networks, and wireless LANs use microwaves.
The infrared waves cannot pass much through obstacles. Therefore, they are in use for short distance communication. Devices like TV remote controllers and VCR use infrared waves.
What is the Difference Between Guided Media and Unguided Media?
Guided Media vs Unguided Media |
|
| Guided media is a medium that sends signals through a solid physical path. | Unguided media is a medium that transmits signals through free space. |
| Direction | |
| There is a specific direction to send signals. | There is no particular direction to send signals. |
| Usage | |
| Used in wired transmission | Helps wireless transmission |
| Examples | |
| Twisted pair, coaxial cable, and fiber optics | Radio wave, microwave, and infrared |
Summary – Guided Media vs Unguided Media
Guided media and unguided media are two types of transmission medium. The difference between Guided Media and Unguided Media is that in guided media, the signals travel through a physical medium while in unguided media, the signals travel through the air.
Reference:
1.“Transmission Media.” IIT, CSE. Available here
Image Courtesy:
1.’FTP cable2’By Baran Ivo – Own work, (Public Domain) via Commons Wikimedia
2.’CoaxialCable’By Raysonho @ Open Grid Scheduler / Grid Engine – Own work, (CC0) via Commons Wikimedia
3.’Fiber optic illuminated’By Hustvedt – Template:One, (CC BY-SA 3.0) via Commons Wikimedia
4.’Erdfunkstelle Raisting 2’By Richard Bartz, Munich aka Makro Freak – Own work, (CC BY-SA 2.5) via Commons Wikimedia