There are different types of communication media that have greatly influenced our lives. All these communication media available around us can be classified in to two big categories namely:
1. The wired technologies and
2. The wireless technologies
This classification holds good for every field wherever there is communication network is involved. Even the computer networks that we have today can be categorized based up on the hardware they are using and the software technology associated with it that interconnects the individual devices. Some examples are:
1. Electrical cable: includes power line communication, G.hn, Home PNA and so on.
2. Optical fibers
3. Radio waves etc.
In this article we shall discuss about the various wired technologies that are used as the communication media. Below we list the wired technologies in the order of the transmission speed they provide i.e., from slowest to the fastest:
Twisted Pair Wire
– This one is perhaps the most widely used wired technology.
– It is mostly employed in the field of telecommunications.
– In a twisted pair wire, there are a number of copper wires that are twisted in to each other so as to form a twisted pair.
– In the twisted pair wire using in telephones there are only two copper strands twisted in to a pair.
– The wired Ethernet is used for computer networking cabling.
– IEEE 802.3 defines the Ethernet.
– It makes use of 4 pairs of the copper cables that support the data as well as the voice transmission.
– What is the purpose of twisting? It reduces the electromagnetic induction as well as the cross-talk.
– The transmission speed in a twisted pair wire lies in the range of 2 million BPS – 10 billion BPS.
– There are two types of twisted pair wire namely: Shielded twisted – pair or STP and Un-shielded twisted–pair or UTP
– Each of the above types comes in a number of ratings that can be used in different areas.
– The two conductors are taken from a simple circuit and are twisted together so as to cancel the EMI or the electromagnetic interference that results because of a number of external sources.
– Equal and opposite signals are carried by the two wires in a balanced pair operation.
– The difference between the two is detected at the destination.
Coaxial Cable or Coax
– This wired technology finds its major use in the television industry, work sites for LANs and buildings.
– This cable is quite simple in construction when compared to the previous one.
– In this, an aluminum or a copper wire is wrapped in an insulating layer which in turn is wrapped in a conductive layer.
– The insulation layer is usually made up of some flexible material possessing a high dielectric constant.
– The purpose of this layer is to minimize the distortion and interference as well.
– The transmission speed lies in the range: 200 million BPS – 500 million BPS.
– The conducting shield is tubular in structure.
– The technology got its name from the fact that the same geometric axis is shared by both the inner conductor and outer sheath.
ITU – T G.hn
– This wired technology makes use of the home wiring i.e., phone lines, coaxial cable, power lines etc. for the creation of a LAN possessing very high speed of the measure eof gigabits per second.
– This fiber is made up of glass.
– Pulses are what that it uses for the transmission of the data.
– This communication media has got a number of advantages over the other three wired communications such as:
1. Reduced transmission losses
2. Provides immunity from electromagnetic radiation
3. Fast transmission speed
4. Provides transmission speeds of the order of trillions of BPS.
– A number of messages can be sent over one optic fiber cable by using different colors of lights for every message.