Computer communication

 

TEACHING COMPUTER NETWORKING	Search this site

NAVIGATION HOME LECTURES LESSON 1 - INTRODUCTION TO TEACHING COMPUTER NETWORKING LESSON 2 - IDENTIFYING THE BENEFITS OF NETWORKS LESSON 3 - USE OF COMPUTER COMMUNICATIONS LESSON 4 - NETWORKS LESSON 5 - COMMUNICATIONS OVER THE TELEPHONE NETWORK LESSON 6 - COMMUNICATION DEVICES LESSON 7 - HOME NETWORKS LESSON 8 - PHYSICAL TRANSMISSION MEDIA LESSON 9 - WIRELESS TRANSMISSION MEDIA IP ADDRESSING MAKING ETHERNET CABLES LABORATORIES ACTIVITIES ATTENDANCE CONTACT ME

Lesson 3 - USE OF COMPUTER COMMUNICATIONS COMMUNICATIONS Computer communications describes a process in which two or more computers or devices transfer data, instructions, and information. Figure 8-1 shows a sample communications system. Some communications involve cables and wires; others are sent wirelessly through the air. As illustrated in this figure, communications systems contain all types of computers and computing devices. For successful communications, you need the following: A sending device that initiates an instruction to transmit data, instructions, or information. A communications device that connects the sending device to a communications channel. A communications channel, or transmission media on which the data, instructions, or information travel. A communications device that connects the communications channel to a receiving device. A receiving device that accepts the transmission of data, instructions, or information.  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. One type of communications device that connects a communications channel to a sending or receiving device such as a computer is a modem. Two examples of communications channels are cable television lines and telephone lines.  USES OF COMPUTER COMMUNICATIONS Computer communications are everywhere. Many require that users subscribe to an Internet access provider. With other computer communications, an organization such as a business or school provides communications services to employees, students, or customers.  Wireless Messaging Services Users can send and receive wireless messages to and from smart phones, cell phones, handheld game con- soles, and other personal mobile devices using three tech- niques: text messaging, wireless instant messaging, and picture/video messaging (Figure 8-3). TEXT MESSAGING A mobile device with text messaging, also called SMS (short message service), capability allows users to send and receive short text messages on a phone or other mobile device. Text mes- saging services typically provide users with several options for sending and receiving messages: Mobile to Mobile: send a message from your mobile device to another mobile device Mobile to E-Mail: send a message from your mobile device to an e-mail address anywhere in the world Web to Mobile: send a message from a text messaging Web site to a mobile device, or request that a Web site alert a mobile device with breaking news and other updates, such as sports scores, stock prices, and weather forecasts Mobile to Provider: send a message by entering a four- or five-digit number assigned to a specific content or wireless service provider, followed by the message, such as a vote for a television program contestant WIRELESS INSTANT MESSAGING Wireless instant messaging (IM) is a real-time Internet communications service that allows wireless mobile devices to exchange messages with one or more mobile devices or online users. Some wireless Internet service providers partner with IM services so that you can use your smart phone or other mobile device to send and receive wireless instant messages. With a compatible IM service, users have these IM options: Mobile to Mobile: use a wireless instant messenger to communicate between two mobile devices Mobile to Personal Computer: use a wireless instant messenger to communicate between a mobile device and a personal computer Web to Mobile: send or forward messages from a personal computer’s instant messenger to a mobile device  Internet — Worldwide collection of networks that links millions of businesses, government agencies, educational institutions, and individuals Web — Worldwide collection of electronic documents on the Internet that users access through a Web browser E-Mail — Transmission of messages and files via a computer network Instant Messaging — Real-time one-on-one communications service on the Internet that notifies you when one or more people are online and then allows you to exchange messages, pictures, files, audio, and video Chat Rooms — Real-time typed conversation among two or more people that takes place on a computer connected to a network that also may allow the exchange of messages, pictures, files, audio, and video Newsgroups — Online areas in which users have written discussions about a particular subject Blogs — Time-stamped articles on a network that reflect the author’s interests, opinions, and personality Wikis — Collaborative Web sites that allow users to create, add to, modify, or delete Web site content RSS — Specification that enables Web content to be distributed to subscribers VoIP — Conversation that takes place over the Internet using a telephone connected to a computer or mobile device or telephone adapter FTP — Internet standard that permits users to upload and download files to and from FTP servers on the Internet Web Folders — Location on a Web server (also known as an HTTP server) to which users publish documents and other files Video Conferencing — Real-time meeting between two or more geographically separated people who use a network to transmit audio and video data Fax Machine or Computer Fax/Modem — Transmits and receives documents over telephone lines  PICTURE/VIDEO MESSAGING With picture messaging, users can send pictures and sound files, as well as short text messages, to a phone or other personal mobile device, or a computer. With video messaging, users can send short video clips, usually about 30 seconds in length, in addition to all picture messaging services. Picture/video messaging service, also called MMS (multimedia message service), typically provides users these options for sending and receiving messages: Mobile to Mobile: send the picture/video from your mobile device to another mobile device Mobile to E-Mail: send the picture/video from your mobile device to an e-mail address anywhere in the world  Users can send and receive text messages, wireless instant messages, and picture/video messages to  and from their smart phones and other computers and devices. Wireless Internet Access Points At home, work, school, and in many public locations, people connect wirelessly to the Internet through a wireless Internet access point using mobile computers, smart phones, handheld game consoles, or other devices. Users access wireless Internet access points with computers or devices that have the necessary built-in wireless capability or the appropriate wireless network card, PC Card, ExpressCard module, or USB network adapter (Figure 8-4). Two types of wireless Internet access points are hot spots and mobile wireless networks. A hot spot is a wireless network that provides Internet connections to mobile computers and other devices. Through the hot spot, mobile users check e-mail, browse the Web, and access any service on the Internet. Three hot spot technologies are Wi-Fi, WiMAX, and Bluetooth. Wi-Fi hot spots pro- vide wireless network connections to users in public locations such as airports, train stations, hotels, convention centers, schools, campgrounds, shopping malls, bookstores, libraries, restaurants, and coffee shops. The coverage range for WiMAX hot spots, can be much wider than Wi-Fi; for example, they can cover an entire city. Bluetooth hot spots provide location-based services, such as sending coupons or menus, to users whose enabled devices enter the coverage range. Sections later in this chapter discuss Wi-Fi, WiMAX, and Bluetooth in more detail. Some hot spots provide free Internet access, some charge a per-use fee, and others require users to subscribe to a wireless Internet service provider, to which they pay per access fees, daily fees, or a monthly fee. Per access fees average Php100, daily fees range from Php20 to Php150, and monthly fees range from Php1,000 to Php5,000  for unlimited access, with the higher monthly fee providing greater coverage areas. A mobile wireless network provides users with high-speed Internet connections, as long as they are in the network’s range. A mobile wireless network usually includes most major cities and air- ports. Subscription fees for unlimited monthly Internet access to a mobile wireless network through a cell phone range from Php1,000 to Php3,000. Fees for notebook computer access are higher, ranging from Php1,500 to Php3,500 per month.