NETWORK AND COMMNICATION

COMMUNICATIONS

Computer communications describe a process in which two or more coputers or devices transfer data,intructions ab information.

Figure 9-1 shows a  sample communications system.some communications inivolve cables and wires,other are sent wirelessly through the air.for successful communications,you need following :

• A sending device
•    A communications device that connects the  sending device to a communications chanel
•  A  communications chanel,ora transmission media on which the data,intructions or informations travel.
• A communications device that connects the communications channel to receiving device.
• A receiving device that accepts the transmission of data,intructions ora information

USES OF COMPUTER COMMUNICATIONS

Computer communications are everywhere.many require that users subscribe to aninternet acces provides communications services to employees,student or customers.

Variety computer communications is blog,chat rooms,email,fax,FTP,instans messaging,internet,news groups,web 20.0,web folders and wikis.

WIRELESS MESSAGING SERVICES

                Users can send and receive wireless messages to and form smartphone,cel phones,hand held gamw consoles ad other mobile devices an computers using three tecniques : text messaging,picture/video messaging and wireless instant messaging (figure (9.2).the type of massaging you use depends primarily on the services affered by the wireless internet service provider (WISP) that works with the cell phone or other mobile device you select.in most cases you can receive these message at no cost but pay a per use or monthly fee to send messages to others.

Figure 9.2  user can send and receive text message,picture/video message and wireless instant message to and from their smart phones and other computers an devices.

Text messaging  a mobile device with text messaging,also called SMS (Short Message Service),capability allows users to send and receive short text messages,tyoically fewer than 300 characters,on a phone or the mobile device or computer.

·         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 messging website to a mobile device or request that a web site alert a moile device with messges of breaking news and other updates,such as sport scores,stoct prices and weather forecasts

·         Mobile to Provider : send message by entering a common short code (CSC),which is 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 contestan or an entry for a sweepstakes.

Picture/video Messaging

User can send picture and sound files,as well as short text message to aphone or other mobile device or a computer.

The video messaging usuallu about 30 seconds in length.thi service also called MMS (Multimedia message service).

If you send apicture message to a phone that does not heve picture,video messaging capability,the phone usually display a text message directing the user to a web page that contains the picture/video message .some online social networks allow you to send a picture/video message to an assigned number to post the message automatically to your online profile.

                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 notebook computers,smart phones,handheld game consoles or other device.

                A hot spot is a wireless network that provides internet connections to mobile computers and device.through the hot spot mobile user check email,brows the web and acces any service on the internet.three hot spot technologies are Wi-Fi,WiMAX and Bluetooth.

                Some hot spot provide free internet acces,some charge a per-use fee,and others require users to subscribe to a WISP,to which they pay per-access fees,daily fees,or a monthly fee.

Per-acces fees average $3,daily fees range form $5 to $20,and monthly fees range from $20 to $60 for unlimited acces with the higher monthly fee providing greater coverage areas.

GLOBAL POSITIONING SYSTEMS

a global positioning system (GPS) is a navigation system that consist of one or more earth –based receivers that accept and analyze signals sent by satellite in order to determine the receiver and a processor.many include a screen display that shows an individual’s location on a map.

Many mobile devices such as smartphones have GPS capability buit into the  device or as an add-on feature.

The first and most used application of GPS technology is to assist people with determining where they are located.the data obtained form a GPS,however can beapplied 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.

HOW A GPS WORKS

 

Groupeware

                Groupwre is software that helps grous of people work together on project and share information over a network.

Voice mail

Voice mail,which functions much like an answering mechine,allows someone to leave a voice message for one ore more people.once digitized the message is stored in a voice mailbox.a mailbox is a storage location on a hard disk in the voice mail system.Some voice mail system can send audio voice mail files to e-mail addresses.other can convert a voice mail files message to a text message for display on a computer or mobile device such as a smart phone,which you them can manage like any other tect message.

WEB SERVICE

Web service describe standardlized software that enables programmers to create applications tht communicate with other remote computers over the Internet or an internal business network.business use web service because this technology provides a means for department to communicate with their online with each other,suppliers,vendors and with clients.

Web serviceoften provede content for mashup.a mashup is a web application that combines services from teo or more sources,creating a new application.ane-commerce business,for example.might determine the address of its closestretail store form its web site and combine (mash) the location with the map from a trevel and mapping web site to provide a web site visitor with driving directions.

NETWORKS

Network is a collection of computers and device connected together via communications devices and transmission media.many business network their comuters together to facilitate communications,share hardware,share data and information,share software and transfer fnd.

The efollowing paragraphs  explain the advantages of using a network.

·         Facilitating communicating- using a network,people communicate efficiently an easily via e-mail,instant messaging,chat rooms ,blogs,wikis online social networks,video telephone calls,online meetings,video conferencing,VoIP,wireless messaging service and groupware.some of these communications such as e-mail,occur within a business’s internal network.other times,they occur globally over the internet.

·         Sharing hardware—in a networked environment,each computer on the network.business and home users network their hardware to save money.