Communication refers to the process of sharing information, messages, and ideas with other people in a particular time and place. There are many forms of communication and these include verbal communication (which is writing and talking) and nonverbal communication (such as facial expressions, body language or gestures). Others are visual communication (the use of images or pictures such as painting, photography, video, or film), and electronic communication (telephone calls, electronic mail, cable television, or satellite broadcasts).
When the term communication is used in a computer context, it refers to telecommunications, which is, data sent from one device to another using communications media such as telephone lines and the airwaves.
In this post you will learn about the types of communication devices.
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Types Of Communication Devices
Communication devices are hardware equipment or media that aid the transmission of data from the source to the destination. These devices also known as communication channels, are capable of transmitting analog or digital signals over the telephone, other communication wire, or wireless media.
Microcomputers have two ways of connecting to each other or other equipment; through a wire/cable network and through the air/wireless network connection. With a wired network connection, the computers and other devices on the network are physically cabled to the network.
A wireless network connection usually uses radio signals to send data through the air between devices, instead of using physical cables. Wired networks are very common in homes, schools, businesses and government establishments. While wired networks tend to be faster and more secure, wireless network have the advantage of allowing easy connections in locations where physical wiring is not possible.
Communication devices used in transmitting data include but not limited to the following: modem, telephone lines, satellites, cellular radios/phones, Bluetooth devices, infrared devices, network interface cards, Wi-Fi devices, and many more.
A lot of computer communications happen over telephone lines. The telephone however, was originally designed for voice transmission only, as such, it typically sends and receives analog signals. In contrast, computers send and receive digital signals only. The modem is a hardware device that enables the computer to send and receive information over telephone lines by converting digital data into an analog signal used on phone lines, and vice versa.
The modem derives its name from “modulation-demodulation”.
Modulation refers to the process of converting signals from digital to analog. Demodulation is the process of converting analog signals to digital. The modem therefore enables digital microcomputers to communicate across analog telephone lines.
Aside the description given above, the word “Modem” can sometimes and most often today, be used to refer to “Broadband Modem” which is a hardware device that connects a computer or router to a broadband network. Two examples of these types of Modems are Cable Modem and DSL Modem. A broadband modem is an external device and it connects to computers and other network devices using either a network cable or over a wireless medium. In either way it uses a network card inside the computer. To avoid confusion, non-broadband modems are also called dial-up Modems.
Modems can be categorized in several ways. Based on mode of connection, we can have external, internal, and wireless modems.
- The external modem stands apart from the computer and connects to the computer’s serial port through a cable. Another cable then connects the modem to the telephone wall jack.
- The internal modem is small plug-in circuit board on the motherboard inside the computer case. The modem connects to the telephone wall jack through a telephone cable.
- The wireless modem, similar to the external modem, connects to the computer’s serial port. It connects to laptops and notebook computers through a USB port. Its wireless nature is in the fact that unlike the external modem, it does not connect to telephone lines but rather sends and transmits through the air.
Twisted pair cables : Most telephone lines seen strung on poles consist of twisted pair cables made of hundreds of copper wires. A single twisted pair ends in a wall jack into which a phone can be plugged. Over the years, telephone lines have been the standard medium for voice and data transmission. However, they are now being phased out by more technically advanced and reliable communication media.
Coaxial cable : This is a high-frequency transmission medium that replaces the multiple wires of telephone lines. It is a transmission line consisting of a plastic tube with solid-copper at the core surrounded by an insulating material with tiny metal strands meshed around it. Also known as coax, it is used to transmit telegraph, telephone, television, and internet signals. It has over 80 times the transmission capacity of twisted pair.
Fiber-optic cable : Fiber-optic cable is a high-speed data transmission medium containing a bundle of thin flexible glass or plastic tubes/filaments through which data can be transmitted as beams of light. A fiber-optic tube can be half the diameter of a human hair. To transmit digital data, pulses of light are sent through the cable by a laser device and the receiving end of the fiber optic transmission translates the light pulses into binary values, which can be read by a computer. Because they transmit data via light waves, fiber optic cables can transfer information at the speed of light, 26,000 times the transmission capacity of twisted pair.
Apart from having the fastest data transfer rate among all transmission media, fiber-optic cables are also less susceptible to noise and interference as compared to copper wires. However, they are more fragile than their metallic counterparts and therefore need more protective shielding. Since fiber optic cables provide fast transfer speeds and large bandwidth, they are used for a large part of the Internet backbone.
Microwave : In the case of microwave as a communications channel, the medium is not a solid substance, but rather the airwave itself as a wireless transmission medium. Microwaves are a form of electromagnetic radiation of extremely high frequency in the range of 100 megahertz to 30 gigahertz (lower than infrared but higher than other radio waves). They are used in radar, radio transmission, cooking, and other applications.
Microwaves are widely used for point-to-point communications because they travel in straight lines in the air and cannot bend with the curvature of the earth like low frequency radio waves. They can therefore transmit information only over short distances. This makes microwave a good medium for sending data between buildings in a city or on a large college campus. For longer distances, the waves must be relayed by using dishes or antennas which can be installed on towers, high rising buildings, and mountain tops in a line-of-sight fashion.
Satellite communication is the use of artificial satellites launched into Earth’s orbit several miles in space for the purpose of sending and receiving communication data between a source and destination. Communications satellites use a wide range of radio and microwave frequencies.
The purpose of communications satellites is to relay telecommunications signal around the curve of the Earth allowing communication between widely separated points. Satellites can send and receive transmissions to and from a variety of devices such as personal satellite dishes used for satellite television and internet service, satellite radio receivers, and satellite phones.
Traditional satellites maintain a stationary orbit 22,300 miles above the Earth and travel at a speed and direction that keeps them in pace with the Earth’s rotation. This makes them appear to be stationary over a given spot in the airspace.
Cellular radio communication is based on a network of transmitters also known as cellular towers used in personal communication systems. Each tower or transmitter which is usually a metal pole with antennas on top, serves a small area called a cell. Cellular radio transmissions are a form of radio signals designed for use with mobile cellular phones also called mobile phones or cellular radios.
When a user begins to make a call, it is picked up by the cell tower in the cell area in which the caller is located. The tower then forwards the call to its cellular company’s Telephone Switching Office from where it travels to the recipient through his/her telephone service provider. Whenever the user passes from one cell to another the mobile receiver switches frequencies automatically.
Bluetooth is standard wireless technology for transmitting data between Bluetooth-compatible devices over short distances (less than 10 meters). It enables devices such as portable computers, cell phones, and other handheld devices to connect to each other and to the internet. Bluetooth is most appropriate for communication between computers or mobile devices and peripheral devices, such as to connect a wireless keyboard or mouse to a desktop computer, and to connect a mobile phone to an earpiece.
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