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3. Data Communications 3.2 Networking. Network Applications  Fax, Voice, and Information Services...

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  • Slide 1
  • 3. Data Communications 3.2 Networking
  • Slide 2
  • Network Applications Fax, Voice, and Information Services Person to Person Communications Group Communications Exchanging Files
  • Slide 3
  • Fax, Voice and Information Services Fax Fax-back services Voice mail On-line services
  • Slide 4
  • Fax A facsimile machine is a telephone copy machine FAX Printout to printout Computer Digital to digital FAXComputer Printout to digital ComputerFAX Digital to printout
  • Slide 5
  • Fax-back services You dial their number, answer a few questions by pressing numbers on your phone, and hang up. The company s fax machine then automatically send you a fax of the information you requested. Your phone Your faxFax-back Service
  • Slide 6
  • Voice mail Automates phone answering and messaging Sophisticated systems have an automated attendant that routes you to the right person when you press the keys of a touch-tone phone Now, it s even possible to leave video voice mail
  • Slide 7
  • On-line services Networks were introduced at home through the large commercial information services such as CompuServe, AOL, and Microsoft Network. You can locate important information or exchange e-mail with other subscribers You can post messages on forums Type messages back and forth in chat mode
  • Slide 8
  • Person to Person Communications Electronic mail E-mail makes it possible to have almost instantaneous communication Cost is low More convenient [email protected] User nameDomain name
  • Slide 9
  • Electronic mail When you send a message, it is stored on a computer somewhere until the addressee reads it. This process is called store and forward Message sent and stored Message retrieved 09:00 A.M. 10:00 A.M.
  • Slide 10
  • Electronic mail E-mail software is used to write, read, and file messages E-mail software courtesy of Microsoft
  • Slide 11
  • E-mail etiquette Don t ever write and send nasty notes impulsively Don t ever refer to third parties in an unflattering way Be careful of inflections, nuances, and sarcasm Don t ever use your company s name in personal postings outside the company Try to act as civilized as possible and do unto others as you would have them do unto you
  • Slide 12
  • Emoticons :-) means I m smiling or indicates a smile or grin :-( means I m sad or unhappy ;-) means I m saying this in jest :*) means clowning :-& means tongue tied ;-/ means skeptical :-\ means undecided :-| means ambivalent |-o means bored Use all uppercase letters WHEN YOU WANT TO SHOUT OUT
  • Slide 13
  • Group Communications Newsgroup Mailing lists Internet relay chat (IRC) Network games Video conferencing
  • Slide 14
  • Newsgroup Usenet (Users Network) is a collection of thousands of ongoing topical discussions called newsgroup Also known as bulletin boards or discussion groups, newsgroups are used by people to share common interests Usenet is not a part of the Internet, or even a network of any kind It s a system for carrying on discussions that can be delivered in a number of ways, the Internet being just one of them
  • Slide 15
  • Mailing lists Mailing lists use e-mail to keep groups informed on topics or events they wish to know about such as when a particular Web site has been updated As you get more involved with the Internet, you may find yourself the recipient of a mass-mailing called a spam
  • Slide 16
  • Internet relay chat (IRC) IRC allows you to chat with other users in real-time Any user with IRC software can go to an IRC computer called an IRC server, create a channel on some topic, and invite others to join in
  • Slide 17
  • Network games The first popular games were text- based The most popular are MUDs (multiuser dialogue) and their variants such as MOOs object-oriented MOOs Graphical games are becoming more popular
  • Slide 18
  • Network games hongkong.gameeast.com hk.games.yahoo.com www.microsoft.com/games/empires Igz2.microsoft.com
  • Slide 19
  • Video conferencing Reduce travel to a minimum Save time Lower the cost
  • Slide 20
  • Exchanging Files Uploading and downloading ASCII and binary files Shared disks FTP on the Internet Binary files as e-mail attachments
  • Slide 21
  • Uploading and downloading Uploading means you are sending the file to another system Downloading means you are transferring a file from another computer to yours Your computer Any other computer Upload Download
  • Slide 22
  • ASCII files ASCII files contain only a limited set of characters and have almost no formatting They are easy to transfer because of their simplicity
  • Slide 23
  • Binary files Binary files have lots of formatting and much of it is specific to the program that created the file A picture, a video, a word processing document, a spreadsheet, a database, an animation, or an executable program don t transfer easily between the networks that use different protocols before being converted with a messy process
  • Slide 24
  • Shared disks It s as easy as moving or copying a file to a public folder. Friends or coworkers can then move it from there to one of their own folders Shared disk
  • Slide 25
  • FTP on the Internet FTP (File Transfer Protocol) is the Internet tool used to transfer files form one machine to another ftp://ftp.loc.gov/pub/american.memory/
  • Slide 26
  • FTP on the Internet Normally you would need a password to log onto the system However, using anonymous ftp, you can browse through computers that allow you to do so by using the name anonymous to log on
  • Slide 27
  • Binary files as e-mail attachments One of the most convenient ways to transfer files is as attachments to e- mail messages If you are sending it across the Internet to a different network, the message will pass through other computes called gateway that may not be compatible
  • Slide 28
  • Binary files as e-mail attachments Binary attachments may be corrupted Needed to use a program to convert the them to an ASCII text file. This is called encoding The recipient muse use a similar program to convert it from ASCII back to binary, decoding
  • Slide 29
  • 2 dominant encoding schemes in use UUcoding (binary to ASCII) and Uudecoding (ASCII to binary) They were originally developed for UNIX-to- UNIX e-mailing MIME (multipurpose Internet Mail Extension) Uses a form of encoding called Base64 which has been better designed to allow messages to pass through a network s various e-mail gateways
  • Slide 30
  • Local Area Networks (LAN) Networks of computers within a small area are called LANs Network resources The whole is greater than the sum of its parts E-mail Sharing peripherals Sharing files Groupware Network applications
  • Slide 31
  • Network resources E-mail The sending of messages to others on the network Sharing peripherals Share expensive peripherals such as plotters, laser printers, and hard disk drives Sharing files Share or exchange files with other users on the network
  • Slide 32
  • Network resources Groupware Groupware have been developed to make team or group activity easier A typical groupware application is a common calendar on which anyone can make entries that others can see Another is a document anyone can add to or change while others can see who is making the changes
  • Slide 33
  • Network resources Network applications The application rests on a computer somewhere on the network, not on your own machine You transfer it to your system when you want to see it A company has to fix or upgrade only one copy on the network Often written in languages such as Java or ActiveX for Internet
  • Slide 34
  • Network users To use a network, you first log on with an ID and a password The ID is assigned by the network administrator The password is selected by you and can (and should) be changed frequently to improve security Normally you ll find printers, hard disks, and other shared assets listed on your system s dialog boxes even though they are located elsewhere on the network
  • Slide 35
  • Network administrators Systems organized into a network are supervised by a network administrator/manager The network manager/administrator is responsible for: Setting up or enforcing network procedures Adding and removing users Assigning Ids and levels of access Troubleshooting problems should users arise and assisting both new and experienced users with problems
  • Slide 36
  • Network administrators One user may be authorized access to correspondence files but denied access to financial analysis files Some users can be given just read-only access, whereas others can be allowed to enter and update the files
  • Slide 37
  • Passwords Don t share your password with anyone Hard to guess. E.g. mix letters with numbers Don t use a password that is your address, pet s name, nickname, spouse s name, telephone no., or one that is obvious such as sequential numbers or letters Longer password, more
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