A path by which details are transmitted derived from one of location to amazing . called communication channel. It is also termed as communication medium or link. The twisted pair wire, coaxial cable, fiber optic cable, microwave, satellite etc. are examples of communication channels.
In a communication channel, information is transmitted as signals (analog signal). The data transmission is measured in bandwidth. The bandwidth will probably be higher if more signals may be transmitted. Actually, the bandwidth measures the volume of information that might be transmitted with the media inside the given stretch of time. For analog signals, bandwidth is represented in hertz (Hz). It means amount of signals transmitted per second. For digital signals, it really is represented in bits per second (bps). Different transmission media have different bandwidths. The higher the bandwidth with the transmission media, the harder information could be transmitted.
Types of Communication Channel:
The communication channel or media is divided into 2 types.
In guided communication media, communication items are directly related to one another via cables or physical media for transmission of data. The data signals are bounded to your cabling media. Therefore, guided media is additionally called bounded media. The guided media are usually employed in LAN. The types of guided or bounded media are:
Twisted Pair Cable: Twisted pair cable is one of the mostly used communication media.
It is employed in local area network (LAN) for data communication between different computers. It is also used in telephone lines to handle voice and data signals.
A twisted pair cable consists of a set of two thin diameter copper wires. These wires are covered by efficiency (including plastic). These couple of wires are twisted together to make a cable. The wires are twisted around each other to reduce (or reduce) interference business twisted pairs inside the cable. Cheapest Multimode Duplex Fiber Optic some pretty interesting stuff?
The data transmission speed through twisted pair cable is about 9600 bits per second in a very distance of 100 meters. However, this transmission speed is lower than coaxial cable or optical fiber.
The twisted pair cable has been the conventional communication channel for voice and data communication. But now its use is reducing because today more reliable communication media can be purchased such as coaxial cable, fiber optic cable microwave and satellite.
Coaxial Cable: Coaxial cable is also termed as Coax. It carries signals of upper frequency ranges than twisted-pair cable. Coaxial cable includes a single solid copper wire, which is called the inner conductor.
Coaxial cable might be used for telephone lines for voice and data transmission with high frequency. The bandwidth of coaxial cable is 80 times higher than those of twisted pair media. Coaxial cable is also widely found in local area network (LAN). It is more costly than twisted-pair wire.
Fiber-Optic Cable: In twisted-pair cable and coaxial cable, details are transmitted by means of electric frequencies. The fiber optic cable uses light to transmit data. The data transmission speed is very high (because fiber-optic cable uses light to transmit data). The data transmission speed can be billions bits per second. Today, most from the telephone companies and cable TV operators are using fiber optic cables inside their networks.
A fiber optic cable consists of tubes of glass (or thin glass fibers) by which data is transmitted as pulses of light. A typical optical fiber consists of a very narrow strand or fiber of glass referred to as the core. It is thinner than the usual real hair. The core is flanked by a concentric layer of glass called Cladding. The diameter of the core is 62.5 microns (I micron = 10-6 meters). The diameter of cladding is approximately 125 microns. The cladding is coated with heat retaining material such as plastic, to create the Jacket.
2. Unguided Media:
In unguided communication media, details are communicated between communication devices by means of wave. Unguided media provides means to transmit data signals but does not guide them along a particular path. The data signals are not bounded to some cabling media. Therefore,. unguided media is also called unbounded media.
This transmission medium is employed when it can be impossible to put in the cables. The data could be transmitted across the world through this medium. The examples of unguided or unbounded media are:
Microwaves: In microwave transmission, data is transmitted through air or space, rather than through cables or wires. Microwaves are high frequency radio waves. These waves are only able to travel in straight lines.
The details are transmitted and received through a microwave station. A microwave station is additionally called relay station or booster. A microwave station contains an antenna, transmitter, receiver, and other equipments which are needed for microwave transmission. Microwave antennas are placed on the high towers or buildings and these they fit within 20 to 30 miles of the other. There may be many microwave stations between the sender and receiver. Data is transmitted in one microwave station to a new. Each microwave station receives signals from previous microwave station and transmits to next station. In this way, info is transmitted over larger distances.
The data transmission speed of microwave transmission can be 150 Mbps. Microwave transmission is utilized in environments where installing physical transmission media is impossible and where line-of-sight transmission is available, it’s used in wide-open areas. Today, it’s used by telephone companies, cable providers, universities etc.
Satellite Communication: A communication satellite is a space station. It receives microwave signals (or messages) from earth stations. Satellite transmission station that can send and receive messages is recognized as earth station. The earth based stations often are microwave stations. Other devices, for example PDAs and GPS receivers, also functions as earth based stations.
Satellites rotate approximately 22,300 miles higher than the earth in precise locations. The communication satellite contains solar powered, transceiver that receives and sends signals. The signals are transmitted derived from one of earth station for the satellite. The satellite receives and amplifies the signals and sends them to a different earth station. This entire process takes just one or two seconds. In this way, data or messages are transferred in one location to a new. Transmitting an indication from ground or earth station to your satellite station in space is known as up-linking along with the reverse is referred to as down-linking. The data transmission speed of communication satellite is extremely high including upto 1 Gbps.
Different communication satellites are used to hold different kinds of information for example cell phone calls, television transmissions, military communication, weather data, and also radio stations use them commercially broadcasting. The global positioning systems and Internet also use the communication satellites.
Radio Broadcast: It can be a wireless transmission medium that can be used to talk information through radio signals in air, over long distance for example between cities and countries.
In this medium, a transmitter is necessary to send messages (signals) and receiver must receive them. To receive the air signal, the receiver posseses an antenna which is located in the variety of signal. Some networks utilize a special device called transceiver used to send also to receive messages available as radio signals. The data transmission speed of radio broadcast can be 54 Mbps.
Cellular Radio: Cellular radio can be a type of radio broadcast that can be used for mobile communications for example cellular telephones and wireless modems. A cellular, telephone is often a telephone device that uses high frequency radio waves to deliver voice and digital messages. Some mobile users connect their laptop computer or other mobile devices to your cellular telephone to access the Web, send and receive e-mail etc. while from an ordinary phone line.