Skip to main content

THE NETWORK TRANSMISSION MEDIUM: ALL STUDENTS MUST KNOW OF....


TWISTED PAIR CABLES

This type of cabling is used for telephone communications and most modern Ethernet networks.  A pair of wires forms a circuit that can transmit data.  A pair of wires forms a circuit that can transmit data.

If the pair of wires are not twisted, electromagnetic noises (ex:motor), will effect the closer wire more, than the further one, therefore causing error.

Twisted pairs are cables that are designed with two independent insulated wires wrapped around each other and with the goal to help to combat electromagnetic interference.

A twisted pair cable comprises of two separate insulated copper wires, which are twisted together and run in parallel. The copper wires are typically 1mm in diameter. One of the wires is used to transmit data and the other is the ground reference.

Twisted-pair cabling is often used in data networks for short and medium-length connections because of its relatively lower costs compared to optical fiber and coaxial cable.

There are two types of twisted pair cables, unshielded twisted pair cable and shielded twisted pair cable.

UNSHIELDED TWISTED PAIR (UTP)

Unshielded twisted pair (UTP) cables are widely used in the computer and telecommunications industry as Ethernet cables and telephone wires. In an UTP cable, conductors which form a single circuit are twisted around each other in order to cancel out electromagnetic interference (EMI) from external sources.

Unshielded means no additional shielding like meshes or aluminum foil, which add bulk, are used.

Typically wrapped in a plastic wrapper. (for mechanical protection)


SHIELDED TWISTED PAIR (STP)

Shielded twisted pair is a special kind of copper telephone wiring used in some business installations. ... To reduce crosstalk or electromagnetic induction between pairs of wires, two insulated copper wires are twisted around each other. Each signal on twisted pair requires both wires.

Shielded twisted pair (STP) cable was originally designed by IBM for token ring networks that include two individual wires covered with a foil shielding, which prevents electromagnetic interference, thereby transporting data faster.

it contains an extra foil wrapping or copper braid jacket to help shield the cable signals from interference. STP cables are costlier when compared to UTP, but has the advantage of being capable of supporting higher transmission rates across longer distances.

The additional covering in STP cable stops electromagnetic interference from leaking out of or into the cable.

STP cables are often used in Ethernet networks, particularly fast-data-rate Ethernets. The effectiveness of the additional covering varies according to the substance used for the shielding, such as:

  • Frequency
  • Thickness
  • Type of electromagnetic noise field
  • Distance from the shield to the noise source
  • Shield discontinuity
  • Grounding practices










COAXIAL CABLES

sometimes known as coax cable, is an electrical cable which transmits radio frequency (RF) signals from one point to another.

Coaxial cable has a distinct thick, round shape because of its interior insulation layer. Its size makes it look very different to other types of cable, such as twisted pair or Ethernet cable. 

Coaxial cables are a popular choice because their shielded design allows the centre conductor to transmit data quickly while being protected from damage and interference.

Coaxial cables are mainly built up of these four different layers:

1.  A centre conductor which is usually a copper wire, which data and video travels through

2.  Surrounding the copper wire is a dielectric plastic insulator

3.  A braided mesh made from copper then helps to shield the cable from electromagnetic interference (EMI)

4.  The external layer is a plastic coating which protects the internal layers from damage


Coaxial cable works by carrying data in the centre conductor, while the surrounding layers of shielding stop any signal loss (also called attenuation loss) and help reduce EMI.

The first layer, called the dielectric, provides distance between the core conductor and the outer layers, as well as some insulation.


FIBER OPTIC CABLES

Fiber-optic cables transmit data via fast-traveling pulses of light. Another layer of glass, called “cladding,” is wrapped around the central fiber and causes light to repeatedly bounce off the walls of the cable rather than leak out at the edges, enabling the single to go farther without attenuation.

Common light sources: LEDs & Lasers


Exclusive e-book by GetResponse and Joanna Wiebe
Labels:

Comments

Post a Comment

Popular posts from this blog

THE OSI MODEL: THE 7 LAYERS IN NETWORKING EXPLAINED

 The Open Systems Interconnection (OSI)  was developed by the International Organization for Standardization in 1984 to enable different types of networks to be linked together.  The model contains seven layers, as shown in the Figure below. These layers describe networking functions from the physical network interface to the software applications interfaces. The intent of the OSI model is to provide a framework for networking that ensures compatibility in the network hardware and software and to accelerate the development of new networking technologies.  Physical layer Provides the electrical and mechanical connection to the network. Examples of technologies working in this layer are Electronic Industries Alliance/Telecommunications Industry Association (EIA/TIA)–related technologies, UTP, fiber, and network interface cards (NICs).  It uses topologies: BUS, STAR, RING, MESH Communication modes: Simplex, Half Duplex, Full Duplex Hardware including ne...
Post a Comment
Read more

FUNDAMENTALS OF NETWORKING

JOB OPPORTUNITIES IN NETWORKING A short discussion can be on: Provide job opportunities that has taken your interest based on the video watched...  WHAT IS A NETWORK?  A network is  a group of computers & other devices that are connected by some type of transmission media. A network can be as small as two computers connected together by a cable or can even be made up of  billions of computers & other devices connected across the world through radio waves, satellites, infra red beams, cable, wireless and even phone lines. The other devices can be referred to cell phones, personal computers, mainframe computers, printers, scanners, security cameras, vehicles and wearable technology devices. TYPES OF NETWORK  Local Area Network (LAN) Metropolitan Area Network (MAN) Wide Area Network (WAN) Personal Area Network (PAN)
5 comments
Read more

HOW CAN CLIENT / SERVER NETWORK MODEL BE A CHANGE FOR YOU??

WHAT IS CLIENT / SERVER?  In the client-server network model (which is sometimes called the client-server architecture or client-server topology), resources are managed by the network operating system through a centralized directory database.  The database can be managed by one or more servers, as long as they have the same network operating system. In the midst of a WINDOWS SERVER   controls network access to a group of computers, this LOGICAL group is known as Windows DOMAIN .  The centralized directory database that keeps user account information & security for the entire group of computers is called AD (Active Directory) .   Each user on the network has his/her own domain level account assigned by the network administrator and kept in Active Directory .   A user can sign on to the network from any computer on the network and get access to the resources that Active Directory allows. The process is managed by AD DS (Active Directo...
4 comments
Read more