A path by which details are transmitted from place to amazing . called communication channel. It can also be referred to as communication medium or link. The twisted pair wire, coaxial cable, fiber optic cable, microwave, satellite etc. are types of communication channels.
In a communication channel, information is transmitted available as signals (analog signal). The data transmission is measured in bandwidth. The bandwidth will probably be higher if more signals could be transmitted. Actually, the bandwidth measures the volume of information that may be transmitted with the media inside the given stretch of time. For analog signals, bandwidth is represented in hertz (Hz). It means number of signals transmitted per second. For digital signals, it can be represented in bits per second (bps). Different transmission media have different bandwidths. The higher the bandwidth from the transmission media, the greater information can be transmitted.
Types of Communication Channel:
The communication channel or media is divided into 2 types.
In guided communication media, communication tools are directly linked with each other via cables or physical media for transmission of internet data. The data signals are bounded with a cabling media. Therefore, guided media is additionally called bounded media. The guided media are often employed in LAN. The examples of guided or bounded media are:
Twisted Pair Cable: Twisted pair cable is one in the mostly used communication media.
It is employed in local area network (LAN) for data communication between different computers. It can also be used in telephone lines to transport voice and data signals.
A twisted pair cable has a pair of thin diameter copper wires. These wires are addressed by heat retaining material (including plastic). These set of wires are twisted together to create a cable. The wires are twisted around the other to attenuate (or reduce) interference from other twisted pairs in the cable. Buy cool stuff you can find.
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 under coaxial cable or optical fiber.
The twisted pair cable has been the common communication channel for voice and data communication. But now its use is reducing because today more reliable communication media are available such as coaxial cable, fiber optic cable microwave and satellite.
Coaxial Cable: Coaxial cable is additionally referred to as Coax. It carries signals of upper frequency ranges than twisted-pair cable. Coaxial cable consists of a single solid copper wire, which is called the inner conductor.
Coaxial cable can be used for telephone lines for voice and data transmission with high frequency. The bandwidth of coaxial cable is 80 times more than that relating to twisted pair media. Coaxial cable can be widely utilized in local area network (LAN). It is more expensive than twisted-pair wire.
Fiber-Optic Cable: In twisted-pair cable and coaxial cable, info is transmitted in the form of electric frequencies. The fiber optic cable uses light to deliver data. The data transmission speed is extremely 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 employing fiber optic cables of their networks.
A fiber optic cable includes tubes of glass (or thin glass fibers) by which details are transmitted as pulses of light. A typical optical fiber is made up of very narrow strand or fiber of glass referred to as core. It is thinner compared to a real hair. The core is encompassed by a concentric layer of glass called Cladding. The diameter of an core is 62.5 microns (I micron = 10-6 meters). The diameter of cladding is about 125 microns. The cladding is coated with heat retaining material like plastic, which is sometimes called the Jacket.
2. Unguided Media:
In unguided communication media, data is communicated between communication devices available as wave. Unguided media provides means for you data signals but does not guide them along a unique path. The data signals usually are not bounded to some cabling media. Therefore,. unguided media is additionally called unbounded media.
This transmission medium is employed when it’s impossible to put in the cables. The data can be transmitted worldwide through this medium. The samples of unguided or unbounded media are:
Microwaves: In microwave transmission, details are transmitted through air or space, rather than through cables or wires. Microwaves are high frequency radio waves. These waves could only travel in straight lines.
The info is transmitted and received through a microwave station. A microwave station is also called relay station or booster. A microwave station contains an antenna, transmitter, receiver, and other equipments which might be essential for microwave transmission. Microwave antennas are placed around the high towers or buildings which are placed within 20 to 30 miles of one another. There may be many microwave stations between the sender and receiver. Data is transmitted in one microwave station to an alternative. Each microwave station receives signals from previous microwave station and transmits to next station. In this way, information is transmitted over larger distances.
The data transmission speed of microwave transmission is about 150 Mbps. Microwave transmission is utilized in environments where installing physical transmission media is not possible and where line-of-sight transmission can be obtained, it really is found in wide-open areas. Today, it really is employed by telephone companies, wire providers, universities etc.
Satellite Communication: A communication satellite can be a space station. It receives microwave signals (or messages) from earth stations. Satellite transmission station that could send and receive messages is termed 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 includes solar powered, transceiver that receives and sends signals. The signals are transmitted from earth station for the satellite. The satellite receives and amplifies the signals and sends them to an alternative earth station. This entire process takes just a few seconds. In this way, data or messages are transferred derived from one of location to a different. Transmitting a sign from ground or earth station to some satellite station in space is named up-linking and the reverse is referred to as down-linking. The data transmission speed of communication satellite is high for example upto 1 Gbps.
Different communication satellites are used to carry different kinds of information for example phone calls, television transmissions, military communication, weather data, and also stereo use them commercially broadcasting. The global positioning systems and Internet also have the communication satellites.
Radio Broadcast: It can be a wireless transmission medium that can be used to communicate information through radio signals in air, over long distance for example between cities and countries.
In this medium, a transmitter must send messages (signals) and receiver is necessary to receive them. To receive the air signal, the receiver has an antenna which is located inside selection of signal. Some networks make use of a special device called transceiver utilized to send and also to receive messages as radio signals. The data transmission speed of radio broadcast is perfectly up to 54 Mbps.
Cellular Radio: Cellular radio is really a form of radio broadcast that is used for mobile communications such as cellular telephones and wireless modems. A cellular, telephone is really a telephone device which uses high frequency radio waves for you voice and digital messages. Some mobile users connect their laptop computer and other mobile devices to some cellular telephone to gain access to the Web, send and receive e-mail etc. while away from a standard phone line.