Q.What are three categories of wired media? Explain them.

Wired media, also known as guided media, refers to transmission media that use a physical conductor to transmit data signals. These media guide the data signals along a specific path. There are three primary categories of wired media:

1. Twisted Pair Cable

   • Description: This cable consists of pairs of insulated copper wires twisted together. The twisting helps reduce electromagnetic interference (EMI) from external sources and crosstalk between adjacent pairs.
   • Types:
     • Unshielded Twisted Pair (UTP): Most common type, widely used in Ethernet networks. It is inexpensive and easy to install but more susceptible to noise.
     • Shielded Twisted Pair (STP): Contains an additional metallic foil or braid shielding around the twisted pairs, offering better protection against EMI and crosstalk than UTP, but it is more expensive and harder to install.
   • Characteristics: Supports data rates up to 10 Gbps (for Cat6a and higher) over limited distances (typically up to 100 meters for Ethernet).
   • Applications: Local Area Networks (LANs), telephone lines.

2. Coaxial Cable

   • Description: This cable consists of a central copper conductor, an insulating layer, a metallic shield (braided wire or foil), and an outer insulating jacket. The metallic shield protects the data signal from external electromagnetic interference.
   • Characteristics: Offers higher bandwidth and better noise immunity than twisted pair cables over longer distances. It can transmit data at rates up to 10 Mbps (for older Ethernet standards) or much higher for broadband applications.
   • Applications: Cable television (CATV), older Ethernet networks (10Base2, 10Base5), broadband internet connections.

3. Fiber Optic Cable

   • Description: This cable transmits data using light pulses through thin strands of glass or plastic (optical fibers). Each fiber consists of a core (where light travels) and a cladding (which reflects light back into the core). …

Wired media refers to the physical cables used to transmit data signals in a network. These cables provide a guided path for electrical or optical signals, forming the backbone of many communication systems. The choice of wired media depends on factors such as required bandwidth, transmission distance, cost, and environmental conditions.

The three primary categories of wired media are:

1. Twisted-Pair Cable

Twisted-pair cable is the most common type of wired media used in local area networks (LANs). It consists of pairs of insulated copper wires twisted together. The twisting helps to reduce electromagnetic interference (EMI) from external sources and crosstalk between adjacent pairs within the cable.

• Construction: Each pair consists of two conductors, typically copper, insulated and twisted around each other. Multiple such pairs are bundled together within an outer jacket.
• Types:
  • Unshielded Twisted Pair (UTP): This is the most widely used type. It has no metallic shield to protect the twisted pairs from external interference. UTP cables are inexpensive and easy to install, commonly found in Ethernet networks (e.g., Cat5e, Cat6).
  • Shielded Twisted Pair (STP): STP cables include an additional metallic foil or braid shield around the twisted pairs (or around each pair individually) to provide better protection against EMI and crosstalk. This makes them more expensive and harder to install than UTP, but they offer better performance in noisy environments.
• Characteristics:
  • Bandwidth: Varies significantly with cable category (e.g., Cat5e supports up to 1 Gbps, Cat6a up to 10 Gbps).
  • Distance: Typically effective up to 100 meters for Ethernet applications before signal degradation becomes significant.
  • Cost: Relatively low.
  • Interference: UTP is susceptible to EMI; STP offers better resistance.
• Applications: Ethernet LANs, telephone lines.

2. Coaxial Cable

Coaxial cable, often simply called "coax," consists of a central copper conductor surrounded by an insulating layer, which is then encased by a braided metallic shield and an outer insulating jacket. This layered construction provides good shielding against external interference.

• Construction:
  • Inner Conductor: A solid copper wire that carries the data signal.
  • Insulator: A dielectric material (e.g., plastic) surrounding the inner conductor, keeping it centered.
  • Braided Shield: A layer of woven copper mesh or aluminum foil that acts as a ground and protects the signal from EMI.
  • Outer Jacket: An insulating protective layer, usually PVC.
• Types: Historically, "Thinnet" (10BASE2) and "Thicknet" (10BASE5) were used for Ethernet, but these are largely obsolete for LANs. The most common type today is used for cable television.
• Characteristics:
  • Bandwidth: Higher bandwidth than twisted-pair over short distances, but less than fiber optic.
  • Distance: Can transmit signals over longer distances than UTP without repeaters (e.g., up to 185 meters for Thinnet, 500 meters for Thicknet).
  • Cost: More expensive than UTP but less than fiber optic.
  • Interference: Good resistance to EMI due to its shielding.
• Applications: Cable television (CATV) distribution, older Ethernet networks, connecting satellite dishes.

3. Fiber Optic Cable

Fiber optic cable transmits data using light pulses through thin strands of glass or plastic, known as optical fibers. It is the most advanced and highest-performing wired media.

• Construction:
  • Core: The central, thin strand of glass or plastic through which light travels. …