What is the name of the transmission media that consists of two insulated copper wires arranged in a regular spiral pattern?

PHYSICAL TRANSMISSION MEDIA

Physical transmission media used in communications include twisted-pair cable, coaxial cable, and fiber-optic cable. These cables typically are used within or underground between buildings. Ethernet and token ring LANs often use physical transmission media.

One of the more commonly used transmission media for network cabling and telephone systems is twisted-pair cable. Twisted-pair cable consists of one or more twisted-pair wires bundled together (Figure 8-24). Each twisted-pair wire consists of two separate insulated copper wires that are twisted together. The wires are twisted together to reduce noise. Noise is an electri- cal disturbance that can degrade communications.

What is the name of the transmission media that consists of two insulated copper wires arranged in a regular spiral pattern?

 Coaxial Cable

Coaxial cable, often referred to as coax (pronounced KO-ax), consists of a single copper wire surrounded by at least three layers: (1) an insulating material, (2) a woven or braided metal, and (3) a plastic outer coating (Figure 8-25).

Cable television (CATV) network wiring often uses coaxial cable because it can be cabled over longer distances than twisted-pair cable. Most of today’s computer networks, however, do not use coaxial cable because other transmission media such as fiber-optic cable transmit signals at faster rates. 

What is the name of the transmission media that consists of two insulated copper wires arranged in a regular spiral pattern?

Fiber-Optic Cable

The core of a fiber-optic cable consists of dozens or hundreds of thin strands of glass or plastic that use light to transmit signals. Each strand, called an optical fiber, is as thin as a human hair. Inside the fiber-optic cable, an insu- lating glass cladding and a protective coating surround each optical fiber (Figure 8-26).

Fiber-optic cables have the following advantages over cables that use wire, such as twisted-pair and coaxial cables:

  • Capability of carrying significantly more signals than wire cables
  • Faster data transmission
  • Less susceptible to noise (interference) from other devices such as a copy machine
  • Better security for signals during transmission because they are less susceptible to noise
  • Smaller size (much thinner and lighter weight)

Disadvantages of fiber-optic cable are it costs more than twisted-pair or coaxial cable and can be difficult to install and modify. Despite these limitations, many local and long- distance telephone companies are replacing existing telephone lines with fiber-optic cables, enabling them to offer fiber Internet access to home and business users. 

What is the name of the transmission media that consists of two insulated copper wires arranged in a regular spiral pattern?


1. Guided media

2. Unguided media

Guided media

Unshielded twisted pair and shield twisted pairCoaxial cable

Fiber optic cable

Unguided media

Radio WavesMicrowavesInfrared