What is the process of transferring data between two or more digital devices?

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• • Lesson 3 - USE OF COMPUTER COMMUNICATIONS

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    • Lesson 3 - USE OF COMPUTER COMMUNICATIONS
    • What is called to transfer a data from one place to another?
    • Which device is used to transfer the data to the system?
    • What means transferring data between two or more devices so that they have the same files?
    • Which method is used to transfer information from one computer to another?

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. 

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.

Cybercafés

When mobile users travel without their notebook computer or Internet-enabled mobile device, they can visit a cybercafé to access e-mail, the Web, and other Internet services. A cybercafé, or Internet cafe, is a coffeehouse, restaurant, or other location that provides personal computers with Internet access to its customers. Cybercafés exist in cities around the world. Although some provide free Internet access, most charge a per-hour or per-minute fee. Some cybercafés also are hot spots.

Global Positioning Systems

A global positioning system (GPS) is a navigation system that consists of one or more earth-based receivers that accept and analyze signals sent by satellites in order to determine the receiver’s geographic location (Figure 8-5). A GPS receiver is a handheld, mountable, or embedded device that contains an antenna, a radio receiver, and a processor. Many include a screen display that shows an individual’s location on a map. Some also function as a portable media player.

Many mobile devices such as smart phones have GPS capability built into the device or as an add-on feature. Some users carry a handheld GPS receiver; others mount a receiver to an object such as an automobile, boat, airplane, farm and construction equipment, or computer.

The first and most used application of GPS technology is to assist people with determining where they are located. The data obtained from a GPS, however, can be applied to a variety of other uses: creating a map, ascertaining the best route between two points, locating a lost person or stolen object, monitoring the movement of a person or object, determining altitude, and calculating speed. Many vehicles use GPSs to provide drivers with directions or other information.

 Collaboration

Many software products provide a means to collaborate, or work online, with other users connected to a server. Two methods of collaboration include collaborative software and document management systems. Collaborative software includes tools that enable users to share documents via online meetings and communicate with other connected users. An online meeting allows users to share documents with others in real time (Figure 8-6). When the online meeting takes place on the Web, it is called a Web conference. In an online meeting, all participants see a document(s) at the

same time. As someone changes the document, everyone in the meeting sees the changes being made. Collaborative software often has chat, white- board, and video/audio conferencing capabilities.

Some companies use document management systems to make collaboration possible among

employees. A document management system provides for storage and manage- ment of a company’s documents, such as word processing documents, presentations, and spreadsheets. Users then access these documents, depending on their needs. A document management system can track all changes made to a document. It also can

store additional information such as the docu- ment’s creation date, the user who created the document, a summary of the document, and any keywords associated with the document. Google Docs is a Web-based document management system that provides basic services to its subscribers at no cost. 

Groupware is software that helps groups of people work together on projects and share information over a network. Groupware is a component of a broad concept called workgroup computing, which includes network hardware and software that enables group members to communicate, manage projects, schedule meetings, and make group decisions. To assist with these activities, most groupware provides personal information manager (PIM) functions, such as an elec- tronic appointment calendar, an address book, and a notepad. A major feature of groupware is group scheduling, in which a group calendar can track the schedules of multiple users and help coordinate appointments and meeting times.

Voice Mail

Voice mail, which functions much like an answering machine, allows someone to leave a voice message for one or more people. Unlike answering machines, however, a computer in the voice mail system converts an analog voice message into digital form. Once digitized, the message is stored in a voice mailbox. A voice mailbox is a storage location on a hard disk in the voice mail system. Some voice mail systems can send digital voice mail files to e-mail addresses. Others can convert a voice mail message to a text message for display on a computer or mobile device.

Web Services

Web services describe standardized software that enables programmers to create applications that communicate with other remote computers over the Internet or over an internal business network. Businesses are the primary users of Web services because this technology provides a means for departments to communicate with each other, suppliers, vendors, and with clients. For example, third-party vendors can use Web services to communicate with their online retailer’s Web site to manage their inventory levels.