Computer communications describes a process in which two or more computers or devices transfer data, instructions, and information. Successful communications requires a sending device that initiates a transmission instruction, a communications device that connects the sending device to a communications channel, acommunications channel on which the data travels, a communications device that connects the communications channel to a receiving device, and a receiving device that accepts the transmission of data, instructions, or information.
2.Identify various sending and receiving devices.
.A sending device initiates the transmission of data, instructions, and information while a receiving device accepts the items transmitted.
- All types of computers and mobile devices serve as sending and receiving devices in a communications system. This includes mainframe computers, servers, desktop computers, notebook computers, Tablet PCs, smart phones, portable media players, and GPS receivers.
3. Describe uses of computer communications.
Communications technologies include the Internet, Web, e-mail, instant messaging, chat rooms, newsgroups, blogs, wikis, RSS, VoIP, FTP, Web folders, video conferencing, and fax machine or computer fax/modem. Users can send and receive wireless messages to and from smart phones, cell phones, handheld game consoles, and other personal mobile devices using text messaging, wireless instant messaging, picture messaging and video messaging. A wireless Internet access point lets people connect wirelessly to the Internet through a wireless Internet access point. A hot spot is a wireless network that provides Internet connections to mobile computers and devices. A cybercafé is a coffeehouse, restaurant, or other location that provides computers with Internet access. A global positioning system (GPS) analyzes signals sent by satellites to determine an earth-based receiver’s geographic location. Many software products provide a means to collaborate, or work online with other users connected to a server. A document management system provides for storage and management of a company’s documents, such as word processing documents, presentations, and spreadsheets. Groupware is software that helps people work on projects or share information over a network. Voice mail allows someone to leave a voice message for one or more people. Web services describe standardized software that enables programmers to create applications that communicate with other remote computers.
- Speed. Sharing and transferring files within Networks are very rapid. thus saving time, while maintaining the integrity of the files.
- Cost. Individually licensed copies of many popular software programs can be costly. Networkable versions are available at considerable savings. Shared programs, on a network allows for easier upgrading of the program on one single file server, instead of upgrading individual workstation.
- Security. Sensitive files and programs on a network are passwords protected or designated as "copy inhibit," so that you do not have to worry about illegal copying of programs.
- Centralized Software Management. Software can be loaded on one computer (the file server) eliminating that need to spend time and energy installing updates and tracking files on independent computers throughout the building.
- Resource Sharing. Resource such as, printer, fax machines and modems can be shared.
- Electronic Mail. E-mail aids in personal and professional communication Electronic mail on a LAN can enable staff to communicate within the building having to leave their desk.
- Flexible Access. Access their files from computers throughout the firm.
- Workgroup Computing. Workgroup software (such as Microsoft BackOffice) allows many users to work on a document or project concurrently.
- A network is a collection of computers and devices connected together via communications devices and transmission media. Advantages of using a network include facilitating communications, sharing hardware, sharing data and information, sharing software, and transferring funds.
5. Differentiate among client/server, peer-to-peer, and P2P networks.
- On a client/server network, one or more computers acts as a server, sometimes called a host computer, which controls access to network resources and provides a centralized storage area, while the other computers on the network are clients that rely on the server for resources. A peer-to-peer network is a simple network that typically connects fewer than 10 computers, each called a peer, that have equal responsibilities and capabilities. P2P is an Internet peer-to-peer network on which users access each other’s hard disks directly and exchange files over the Internet.
6. Describe the various network communications standards.
- A network standard defines guidelines that specify the way computers access a medium, the type(s) of medium, the speeds on different types of networks, and the type of physical cable or wireless technology used. Network communications standards include Ethernet, token ring, TCP/IP, 802.11 (Wi-Fi), Bluetooth, UWB, IrDA, RFID, WiMAX, and WAP. Ethernet specifies that no central computer or device on the network should control when data can be transmitted; that is, it allows nodes to contend for access to the network. Token ring requires devices to share or pass a special signal, called a token. TCP/IP (short for Transmission Control Protocol/Internet Protocol) divides data into packets. 802.11 is a series of standards for wireless devices. Bluetooth uses short-range radio waves to transmit data. UWB, which stands for ultra-wideband, specifies how two USB devices use short-range radio waves to communicate at high speeds. IrDA transmits data wirelessly via infrared light waves. RFID uses radio signals for communications. WiMAX, also called 802.16, is a newer network standard developed by IEEE that specifies how wireless devices communicate over the air in a wide area. The Wireless Application Protocol (WAP) allows wireless mobile devices to access the Internet.
7. Explain the purpose of communications software.
- Communications software helps users establish aconnection to another computer or network; manages the transmission of data, instructions, and information; and provides an interface for users to communicate with one another.
8. Describe various types of lines for communications over the telephone network.
- The telephone network uses dial-up lines or dedicated lines. A dial-up line is a temporary connection that uses one or more analog telephone lines for communications. Adedicated line is an always-on connection established between two communications devices. Dedicated lines include ISDN lines, DSL, FTTP, T-carrier lines, and ATM. ISDN is a set of standards for digital transmission of dataover standard copper telephone lines. DSL transmits at fast speeds on existing standard copper telephone wiring. FTTP, or Fiber to the Premises, uses fiber-optic cable to provide extremely high-speed Internet access to a user’s physical permanent location. Two specific types of FTTP are FTTH (Fiber to the Home) and FTTB (Fiber to the Building). A T-carrier line is a long-distance digital telephone line that carries multiple signals over a singlecommunications line. ATM (Asynchronous Transfer Mode) is a service that carries voice, data, video, and multimedia at extremely high speeds.
9. Describe commonly used communications devices.
- A communications device is hardware capable of transmitting data between a sending device and a receiving device. A modem converts a computer's digital signals to analog signals for transmission over standard telephone lines. An ISDN modem transmits digital data to and from an ISDN line, while a DSL modem transmitsdigital data to and from a DSL line. A cable modem, sometimes called a broadband modem, is a digital modem that sends and receives digital data over the cable television network. A wireless modem uses the cell phonenetwork to connect to the Internet wirelessly from mobile computers and devices. A network card is an adapter card, PC Card, ExpressCard module, USB network adapter, or flash card that enables a computer or device that does not have built-in networking capability to access a network. A wireless access point allows computers and devices to transfer data wirelessly. A router connects multiple computers or other routers together and transmits data to its correct destination on the network.
10.Discuss different ways to set up a home network.
- With computers getting cheaper and cheaper these days, it is not uncommon for a household to have more than one PC. If that describes you, then you have probably found yourself in the situation where you wished you could access the other PC to retrieve a file, use the printer attached to the other PC, play multi-player computer games, or most importantly share your broadband Internet access such as cable or DSL modem with the other PC. To accomplish this all you need is a home network where you connect two or more PCs. There are several ways of doing this with the main difference being cost, security, and reliability.A home network connects multiple computers and devices in a home. An Ethernet network connects each computer to a hub with a physical cable. A home powerline cable network uses the same lines that bring electricity into the house. A phoneline network uses existing telephone lines in a home. Most home networks use a Wi-Fi network, which sends signals through the air at distances up to 1,500 feet in some configurations.
11. Identify various physical and wireless transmission
media.
- Transmission media consist of materials or substancescapable of carrying one or more signals. Physicaltransmission media use tangible materials to sendcommunications signals. Twisted-pair cable consists ofone or more twisted-pair wires bundled together. Coaxial cable consists of a single copper wire surrounded by at least three layers: an insulating material, a woven or braided metal, and a plastic outer coating. Fiber-optic cable consists of thin strands of glass or plastic that use light to transmit signals. Wireless transmission media send communications signals through the air or space. Infrared (IR) sends signals using infrared light waves. Broadcast radio distributes radio signals through the air over long and short distances. Cellular radio is a form of broadcast radio that is used widely for mobile communications. Microwaves are radio waves that provide a high-speed signal transmission. A communications satellite is a space station that receives microwave signals from an earth-based station, amplifies the signals, andbroadcasts the signals back over a wide area.
