Transmission media

• What is Transmission media in a computer network?

A system or material that can mediate the propagation of signals for telecommunications purposes is referred to as a transmission medium. Typically, signals are applied to a wave of some sort that is appropriate for the selected medium. For instance, data may modulate the sound, and while air is a common transmission channel for sounds, solids and liquids can also be used. A useful transmission medium for electromagnetic waves like light and radio waves is a vacuum or air. Although a physical substance is not necessary for the propagation of electromagnetic waves, these waves are typically impacted by the transmission medium they pass through, for example, by absorption, reflection, or refraction at the interfaces between media. Therefore, waves can be transmitted or guided using technical devices. As a result, transmission media like copper cables or optical fibers are employed.

Twisted pair wires, coaxial cables, dielectric-slab waveguides, and optical media like optical fiber can all be used to transfer electromagnetic radiation. Any physical substance, such as water, air, glass, or concrete, that is transparent to a particular wavelength may also allow it to pass through. Since sound is by definition the vibration of matter, it needs a physical medium to be transmitted, much like heat energy and other types of mechanical waves. Science has historically used several other ideas to describe the transmission medium. However, it is now understood that electromagnetic waves can go across the "vacuum" of free space since they do not need a physical transmission medium. areas where there is an insulative vacuum in the presence of free electrons, holes, or ions, can become conductive for electrical conduction.

 

Types of Transmission Media in Computer Networks

        Unguided Transmission Media

what is unguided Transmission Media?       

They are also known as wireless or unbounded media and help transmit electromagnetic signals without the use of a physical medium. Here, air is the media. There is no physical connection between the transmitter and receiver. These transmission medium are less secure than directed media despite being utilized over longer distances. The following are the three main types of wireless transmission media.

What are the advantages and disadvantages of unguided transmission media?

Advantages:

• Simple setup because there is no need for wiring between individual nodes.
• The service is portable since nodes are easily transportable from one location to another.
• By simply swapping credentials, new nodes can be connected.

Disadvantages:

• Due to the vulnerability of signals, data security is at risk.
• Weather conditions may have an impact on data transmission.
• When there are numerous wireless signals, there is signal interference.

Type of Unguided Media:

•  Radio Wave
•  Microwave
•  Infrared

_Radio Waves_

Electromagnetic waves with frequencies between 3 kHz and 1 GHz are commonly referred to as radio waves, and those with frequencies between 1 and 300 GHz are referred to as microwaves, even though there isn't a clear cut boundary that separates the two. However, the behavior of the waves, as opposed to their frequency, is a stronger classification criterion. Radio waves are often omnidirectional. When a radio transmitter uses an antenna, radio waves are sent out in all directions. The sending and receiving antennas do not need to be in alignment as a result. The waves that a sending antenna emits can be picked up by any receiving antenna. The omnidirectional property also has a disadvantage.

Radio waves from one antenna that use the same frequency or band as another antenna's radio transmissions can interfere with them. Radio waves, particularly those that propagate in the sky mode, have a long range. As a result, radio waves, such as AM radio, are a great choice for long-distance broadcasting (AM radio ranges from 535 to 1705 kHz). Radio waves, particularly those with low and medium frequencies, can pass through walls. This characteristic has the potential to be both advantageous and detrimental. Because an AM radio, for instance, might pick up signals within a building, it is useful. This is a disadvantage because we are unable to restrict communication to just the interior or exterior of a structure.  Radio spectrum is smaller than the microwave band. The radio wave band is small—just under 1 GHz—in comparison to the microwave band.

_Micro waves_

Microwaves are electromagnetic waves with a frequency between 1 and 300 GHz. Microwaves have only one direction. Microwave waves can be precisely focused when they are transmitted by an antenna. Therefore, it is necessary to align the sending and receiving antennas. Unambiguously, the unidirectional attribute offers benefits. An antenna pair can be aligned without affecting another antenna pair that is also aligned. 

_Infrared_

A high-frequency wave that falls between "300 GHz and 400 THz" is infrared. Line-of-sight propagation is employed in the infrared transmission, which is used for short-distance communication. Since infrared transmission uses high-frequency waves, which cannot pass through walls, you can clearly distinguish between communication occurring inside and outside of a building. There are no dangers of intervention in this method. The remote control used to run AC, television, and music systems is the most common instance of infrared transmission media. the frequency of the electromagnetic wave rises and we travel from the radio wave toward the visible light, the electromagnetic wave acts more like light. The television receives infrared waves that are emitted by the remote control.

Infrared waves are more secure when it comes to security because there is no possibility of eavesdropping as the infrared wave does not even penetrate the wall. Therefore, using infrared transmission does not even need a license.  these types of transmission media are unguided. Additionally, we now understand the modes of propagation that allow electromagnetic waves to go from source to destination.

Guiding Transmission Media

   Guiding Transmission Media

what is guiding Transmission Media?

Media that is guided is sometimes referred to as wired or confined media. These mediums are made up of wires that are used for data transmission. A physical connection between the transmitter and receiving devices is made by guided media. Physical linkages are used to guide signals along a restricted path. These transmission media are utilized for shorter distances because of physical restrictions on the signal's ability to pass through them.

Twisted Pair Cable 

Two insulated conductors of a single circuit are twisted together in this form of the transmission medium to increase electromagnetic compatibility. These cables are the ones that are utilized for transmission the most. These are bundled together in sheaths for protection. They lessen crosstalk between neighboring pairs and electromagnetic radiation from pairs. Overall, it enhances the ability to reject exogenous.

Advantages:

• It is frequently used to transport both digital and analog data.
• It is comparatively simple to implement and end.
• It is the least expensive transmission medium for short distances.
• A broken twisted pair cable only affects a small fraction of the network.
• less susceptible to electrical interference from surrounding wires or equipment.
• They cause interference.
• Short lengths yield the best results.
• expensive performance
• There is little weight in the twisted-pair wire.
• The use of twisted pair cable is adaptable.
• Connecting twisted pair cables is simple.
• These cables are appropriate for voice and data networks.

Disadvantages:

• It produces signal distortion quite successfully.
• There is a lot of attenuation.
• It supports 10 Mbps on a 10BASE-T up to a distance of 100 meters, which is regarded as low bandwidth.
• It offers little security and is rather simple to tap.
• They may be easily broken because they are thin.
• Low resilience (must be maintained regularly).
• Electromagnetic interference is a possibility (EMI).

Unshielded Twisted Pair Cable (UTP)

 These cables are made up of two insulated copper wires that have been wound around one another. These transmission media types can block interference without a physical shield. Unshielded twisted pairs are inexpensive and easy to set up. These offer a fast connection.

Advantages:

• Easy to handle.
• that cables are used in most of the networking architecture.
• Less expensive compared to other networking media types.
•  designed to counter EMI, RFI, and also crosstalk.
• easy to handle.
• The majority of networking architectures employ cables.
• flexible, significantly simplifying installation.
• less pricey and more affordable than other forms of networking media.
• the most compatible cable, can be used with most other significant networking systems and doesn't need to be grounded.
• The wire that is available for networking purposes is the cheapest.

Disadvantages:

• this used up to a cable segment length of about 100 meters only.
• UTP cable should follow specifications for the number of twists or braids permitted per meter of cable to reduce crosstalk.
• Bandwidth is limited.
• Unable to provide secure transmission of data.
•  external interference like EMI and RFI.
• susceptible to noise.
• It is more susceptible to interference compared to most of the other cable types. 

 Shielded Twisted Pair (STP)

A foil shield was used to protect this twisted wire from outside interference. Greater data transmission rates are made possible by the insulation included in certain types of twisted wire. These are used in telephone lines' data, voice channels, and fast-data-rate Ethernet.

Advantages:

• Better performances at a higher data rate in comparison to UTP.
• Eliminates crosstalk.
• Comparatively faster.
• Easily terminated with a modular connector.

Disadvantages:

• Higher cost per foot of wire.
• More expensive than UTP.
• A higher attenuation rate.
• Difficult and maintain.

 optical fiber cables

These tiny glass strands, also known as fiber optic cables, are used to direct light along their length. These are frequently utilized for long-distance communications and incorporate numerous optical fibers. These cables can transmit enormous volumes of data over long distances without the need for signal repeaters, in contrast to other materials. Less maintenance is required, which lowers costs and increases the dependability of the communication system. Both unidirectional and bidirectional types of these are possible.

Advantages:

• Broadband outperforms copper cables
• less power waste and longer distances for data transfer
• 
  
• The resistance of the optical cable to electromagnetic interference
• Fiber cable is 4.5 times larger than copper lines, which is ideal.
• Cable uses less space than copper wires since they are lighter and thinner.
• Because there is less weight, installation is quite simple.
• The majority of acidic elements that damage flexible copper wires are repelled by this cable.
• Compared to the copper wire of equal length, optical fiber cable is frequently produced more affordably.
• Light travels at the universe's fastest speed, making signals far faster.
• Optical fiber.

Disadvantages:

• These cables are very difficult to merge so there’ll be a loss of beam within the cable
• The cost of installing the wires is reasonable. They are less durable due to wiring. Typically, optical fiber requires specialized equipment.
• When fitting, these cables are quite fragile.
• 
  
• Compared to copper wires, these cables are more fragile.
• To verify fiber cable transmission, specialized equipment is required.
• Installing fiber optic cable is expensive. To install fiber optic lines, specialized installers and pricey splicing equipment are required.

    Coaxial cable 

These guided transmission mediums' insulating layer conveys data in baseband and broadband modes. Two parallel, individually insulated conductors are used in coaxial cables constructed from PVC/Teflon. These wires efficiently transmit electrical signals at high frequencies. To maintain a constant conductor spacing for effective transmission line operation, the dimensions of the cable and connections are maintained.

Investigate no-cost networking courses

This is a multi-layer printed circuit board with transverse electromagnetic (TEM) transmission media built on the inner layers. They are utilized when high- or low-level RF signals need to be isolated from nearby circuitry. Printed circuit transmission lines of this kind sandwich a signal trace between the upper and lower ground planes. Strip line reduces emissions because homogenous dielectric totally encloses electromagnetic radiation. In addition to reducing emissions, it also provides protection against incoming spurious signals.

Advantages:

• A coaxial cable is less expensive.
• It has a high level of physical resistance.
• It is extremely EMI-resistant.
• The channel capacity is excellent.
• High transmission rates are present.
• with a tiny diameter.
• Compared to twisted pairs, it is less vulnerable to noise interference.
• Coaxial cable, which has superior shielding materials, DOES have a high transfer rate.
• easy to expand for flexibility and to wire.
• Compared to twisted pairs, it facilitates the transmission of signals with large bandwidth.
• Low mistake rates lead to noise immunity.

Disadvantages:

• The cost of installation is high.
• Maintenance costs are also significant.
• flexible design is rigid.
• Newer networking standards are not compatible.
• It's hefty.
• It has a bigger security issue.
• There is no high-speed transmission support.
• To avoid interference, it needs to be grounded.
• Its baseband broadcast prevents the integration of audio and video.
• Wiring ducts must have greater space than twisted pairs.

Microstrip line 

Although microstrip lines are similar to strip lines and are present above the ground plane, they are not sandwiched. These can be produced using any technology in which a substrate dielectric layer separates the conductor from the ground plane. Microwave frequency signals are converted using these transmission methods. Microstrip is also employed in constructing microwave couplers, filters, power dividers, antennas, etc. It is less expensive than the conventional waveguide technique.

What are the tools used for network cables

•  Crimping Tools

Wire Cutter:  use any ordinary wire cutter tool or a wire cutter tool specifically made for twisted-pair cable to cut the network cable to the desired length from the bundle. Additional blades for stripping the wire are generally included with twisted-pair wire cutters.

Wire Stripper: The network cable's outer and inner jackets are removed with this tool. Typically, all common twisted-pair wire cutters come with wire strippers, so you won't need to buy this item separately.

Crimp Tool: The connectors are connected to the cable using this tool. This gadget typically comes with a wire cutter and a wire stripper as well. Therefore, you do not need to purchase a wire-cutter and wire-stripper separately if you purchase a crimp tool.

• Testing Tools

Cable Certifier: This tool carefully examines a network cable and verifies that the installation complies with a specific wiring standard, such as Cat 5e, Cat 6, Cat 6a, and so on. The total segment length, crosstalk, noise, wiremap, resistance, impedance, and the capacity to transport data at the cable's maximum frequency rating can all be checked and tested using this instrument.

Basic cable tester: purchase and use this device to control your network cables if you cannot afford a network cable certifier. This device offers the remaining capabilities of a

network cable certifier in addition to verifying the cable installation. It may check for cable breaks, crosstalk, and length issues. Additionally, it can determine whether or not the connections on a network cable's two ends are securely fastened.

Tone generator and probe: This tool is intended to locate network cables without labels. The tone generator and the probe are the two parts that make up this device. Tones or signals are created by the tone generator and sent over the network wire. These signals are picked up by the probe at the opposite end of the cable.

This tool can be used to locate network cables that connect distant locations to a central location. This device can be used, for instance, to determine which network cable connects back to an end device when working on a patch panel or switch.

To establish which network cable is linked to the tone generator, place the tone generator at one end of the connection and use the probe on the other side.

Time domain reflectometer: This tool is used to determine the length and location of cable breaks in network cables. On one end, this gadget emits a signal while measuring how long it takes for the signal to get to the other end of the wire. This tool can also be used to identify cable breaks. For instance, you can get an approximate idea of the cable break's location with this equipment.

 

What metals are used to make electrical wires and cables?

Copper 

The most typical metal found in wires and cables is copper. The material is probably copper. This reddish-brown metal, which has atomic number 29, is now the material of choice for cables and other wiring. A metal with strong conductivity is copper. That means copper is a good material for electrical wires since electricity can easily flow through it. Comparatively speaking to other metals, copper is also rather affordable.

 A ductile metal may bend, flex, and fold without harming the wires, cables, or insulation up to a point. Additionally, copper is moldable, making it simple to construct cables and wires as it takes shape.

 Copper is thermally resistant, which is a major additional advantage when utilizing copper for electrical lines. Wires and cables that are thermally resistant can tolerate a lot of heat without getting damaged or starting an electrical fire. For this reason, copper electrical lines and cables are significantly safer to use than those made of other metals.

Gold

Another often used metal in cables and wires is gold. Due to its low cost as the only conductor, it is typically coated over other metal strands. Compared to copper, silver, and aluminum, gold has a higher level of electrical conductivity and is highly conductive. For a number of reasons, copper and other metal wires are frequently thinly plated in gold at connection points. The most typical type has wires that are incredibly thin, which can occasionally reduce conductivity and capacity.

 Additionally, gold doesn't develop any surface oxides and is very solderable. Gold is a noble metal because, under normal circumstances, it does not chemically react. Noble metals exhibit exceptional chemical resistance even at high temperatures. Additionally, gold resists corrosion very well. It has good wear resistance and is alloyed with modest amounts of nickel or cobalt.

Gold is a vital component of electrical wires and cables because of the flexibility and endurance of its coating. Because of its durability and effectiveness, gold is frequently utilized in wiring for home electronics. The only drawback to utilizing gold is its price; you can probably get the same effects by using copper wire or cable instead.

Silver

One of the most conductive metals is silver. Silver is a strong electrical conductor despite the fact that it oxidizes, which is why you may use it in cables and lines.

Silver has exceptional tensile strength and is flexible and bendable enough to allow for daily use of electrical wires. Silver, on the other hand, costs more and is a more expensive metal to use for wiring and cabling. The second drawback of silver is that it reacts to oxidation considerably more quickly than copper and aluminum, which implies that those metals can endure environmental influences for a much longer period of time. Silvers have a high rate of degradation compared to their cost and availability, which might make them a poor choice for wiring and cables in many situations. Over time, all wires deteriorate.

Aluminum

Due to its affordability and availability, aluminum is a frequently used metal for wires and cables. Since more than a century ago, cables and wires have safely used aluminum, a superb electrical conductor.

Aluminum is strong and ductile, which means that you can readily bend and flex it to move and shape it anyway you need to. Due to its low weight and ability to withstand higher tensile forces than heavier wires, aluminum wiring is frequently used for high-voltage lines. This allows the aluminum wire or cable to live longer. Additionally corrosion-resistant is aluminum. In other words, compared to silver or gold, an aluminum wire has a significantly higher standard of living. Additionally, aluminum provides twice as much conduct per pound of copper wiring. Aluminum is a useful material for wires and cables that will be running a current for extended periods of time because it is also thermally robust.

 

 Tungsten

Wolfram, another name for tungsten, is a less popular metal. It is a particularly refractory metal, which means that it is particularly robust and resistant to heat and wear. This metal is frequently added to steel to make it harder and stronger. Because tungsten has the greatest melting point of any metal, it has also been utilized in wiring.

Since ancient times, tungsten has been utilized in wiring as electrodes, electron tube filaments, and lighting filaments. Due to its exorbitant cost, tungsten is often only employed in extreme temperature applications.