very Excelent Result of AVG 9.0 proofed.

The AVG virus database contains known virus definition. AVG virus experts work hard to identify and explain the latest viruses as soon as these become known (which happens every day), and add the definition to the AVG virus database. Via the update process, these new definitions are downloaded to your computer so that you are always reliably protected even against the latest threats.

Online Threats

Nowadays, there are far more threats out there than plain viruses. You have probably come across the term spyware as well, however, authors of hateful codes and dangerous websites are very modern, and new kinds of threats emerge quite often, the vast majority of which are on the Internet. Here are some of the most common:

Exploit is a malicious code that takes advantage of a flaw or vulnerability in an operating system, Internet browser, or other essential program.

Social engineering is a common term for various techniques used to trick people into giving away their personal information (passwords, bank account details, credit card numbers etc.). A typical example of social engineering is phishing – an attempt to acquire sensitive personal data by shamming a trustworthy and well-known organization. Usually, the potential victims are contacted by a bulk e-mail asking them to e.g. update their bank account details. In order to do that, they are invited to follow the link provided which then leads to a fake website of the bank.

Scam can be also considered a kind of social engineering; it includes false job offers, or ones that will abuse the workers for illegal activities, summons to withdraw a large sum of money, fraudulent lotteries and the like.

Hoax is a bulk e-mail containing dangerous, alarming or just bothering and useless information. Many of the above threats use hoax e-mail messages to spread.

Finally, malicious websites are ones that deliberately install malicious software on your computer, and hacked sites do just the same, only these are legitimate websites that have been compromised into infecting visitors.

To protect you from all of these different kinds of threats, AVG includes these specialized components:

·	Anti-Virus to protect your computer from viruses,
·	Anti-Spyware to protect your computer from spyware,

·	Online Shield (only in AVG Professional) to protect you from both viruses and spyware when surfing the Internet,
·	Link Scanner to protect you from other online threats mentioned in this chapter.

I am recommend you that daily update the AVG virus Database. To keep protected from the latest virus. And you very comfortable when you daily update the avg antivirus against the latest threats.

AVG Interface

System plate Icon

AVG 9.0 Free Edition launches automatically upon Windows startup, and you can see its icon in the system tray (right floor part of the screen). The icon indicates the current Security Status, i.e. whether AVG is working properly or not.

The purpose of the Security Status is to warn you instantly if there is a problem: The AVG icon in the system tray (usually right bottom corner of your screen, see picture) shows an exclamation mark, and warning bubbles pop up above the system tray. How do I fix error Security Status?

Main Screen

The main screen is the front of the AVG application, offering an overview of all installed mechanism and allowing you to access all functions. To display the Main Screen, either:

·	Double-click the AVG icon (on the desktop, or in the system tray), or
·	Use the Start menu -> Programs -> AVG 9.0 Free Edition -> AVG User Interface

What can I see on the Main Screen?

To shut down AVG Interface, use the Main Screen -> Main Menu File -> Exit.

Please note that you only close the interface indeed; the AVG system keeps running in the computer memory at all times.

Yahoo Messsenger Free Calls all over the world

You can now make free calls from your pc to any mobile in the world.All you need is a Yahoo messenger,a mic and a decent internet connection.I'm now using this free call method for over a month now and the great thing is that, this trick can be used to make unlimited call to mobiles all over the world and not limited to United states.It even works to make free local mobile calls in India.


So how do we make a call from pc to mobile phone for free.
Install Yahoo messenger ,incase you don't have it (go for the latest one which have voice support).
Sign into your yahoo messenger.
Configure your microphone and headset(don't use speakers as it cause disturbances)
Inside your Yahoo messenger dial 18003733411 and press enter.
Now a small window pops up like the one shown below.


An operator greets you with a recorded welcome message along with an advertisement and asks you to select one of the Free411 service.Just hear the services options until they say the last one as “Free Call”.When you hear this,don't press any number on your keyboard and instead SAY “Free call” loudly on your microphone connected to your PC.


After this voice message is detected by their system ,they will run a short advertisement of their sponsor and make sure you don't press any number at this time.
WAIT UNTIL YOU HEAR THIS MESSAGE “Please dial the phone number country code first,don't forget to dial 1 for north america”
After you hear this message ,immediately dial the destination number of your choice along with the country code.(eg for north america it's 1 and for india it's 91)
Your call will get connected and you can talk for 7 minutes continuous for free.When it gets disconnected, repeat the same procedure again.You can make multiple and unlimited calls with this service.


It was never easy to make a free international call like this before
So what's the catch?
FREE411 service toll-free number is based in USA.This company gets paid for the advertisements from sponsors.


Are there any limits on the number of call which we can make?


No.There is no limit on the number of free calls which can be made through this system.
So enjoy this trick to make free international and local calls and make sure you don't abuse the system.

To connect to another computer using Remote Desktop Web Connection

1. Ensure that Remote Desktop Web Connection is installed and running on the Web server. For more information, see Setting up Remote Desktop Web Connection.
2. Ensure that your client computer has an active network connection and that the WINS server service (or other name resolution method) is functioning.
3. On your client computer, start Microsoft Internet Explorer.
4. In the Address box, type the Uniform Resource Locator (URL) for the home directory of the Web server hosting Remote Desktop Web Connection.
   The URL is "http://" followed by the Windows Networking name of your server, followed by the path of the directory containing the Remote Desktop Web Connection files (default = /Tsweb/). (Note the forward slash marks.) For example, if your Web server is registered with the WINS server as "Admin1", in the Address box you type: http://admin1/tsweb/, and then press ENTER. The Remote Desktop Web Connection page appears on the screen.
5. In Server, type the name of the remote computer to which you want to connect.
6. Optionally, specify the screen size and logon information for your connection.
7. Click Connect.

Notes

• Remote Desktop Web Connection requires Internet Explorer 4.0 or higher.

Remote Desktop overview about working Remotely

                                                      
                                                 Remote Desktop overview

With Remote Desktop on Windows XP Professional, you can have access to a Windows session that is running on your computer when you are at another computer. This means, for example, that you can connect to your work computer from home and have access to all of your applications, files, and network resources as though you were in front of your computer at work. You can leave programs running at work and when you get home, you can see your desktop at work displayed on your home computer, with the same programs running.
When you connect to your computer at work, Remote Desktop automatically locks that computer so no one else can access your applications and files while you are gone. When you come back to your computer at work, you can unlock it by typing CTRL+ALT+DEL.
Remote Desktop also allows more than one user to have active sessions on a single computer. This means that multiple users can leave their applications running and preserve the state of their Windows session even while others are logged on.
With Fast User Switching, you can easily switch from one user to another on the same computer. For example, suppose you are working at home and have logged on to the computer at your office to update an expense report. While you are working, a family member needs to use your home computer to check for an important email message. You can disconnect Remote Desktop, allow the other user to log on and check mail, and then reconnect to the computer at your office, where you see the expense report exactly as you left it. Fast User Switching works on standalone computers and computers that are members of workgroups.
Remote Desktop enables a variety of scenarios, including:

• Working at home - Access work in progress on your office computer from home, including full access to all local and remote devices.
• Collaborating - Bring your desktop to a colleague's office to debug some code, update a Microsoft PowerPoint slide presentation, or proofread a document.
• Sharing a console - Allow multiple users to maintain separate program and configuration sessions on a single computer, such as at a teller station or a sales desk.

To use Remote Desktop, you need the following:

• A computer running Windows XP Professional ("remote" computer) with a connection to a Local Area Network or the Internet.
• A second computer ("home" computer) with access to the Local Area Network via network connection, modem, or Virtual Private Network (VPN) connection. This computer must have Remote Desktop Connection, formerly called the Terminal Services client, installed.
• Appropriate user accounts and permissions.

To set up this computer to use Remote Desktop

1. Open System in Control Panel.
2. On the Remote tab, select the Allow users to connect remotely to this computer check box.
3. Ensure that you have the proper permissions to connect to your computer remotely, and click OK. You must be an administrator or a member of the Remote Desktop Users group on your computer. For more information, see To allow other users to connect to your computer.

Notes

• You must be logged on as an administrator or a member of the Administrators group to enable the Remote Desktop feature.
• To open a Control Panel item, click Start, click Control Panel, and then click the appropriate icon.

Windows Explorer keyboard shortcuts

Press	To
END	Display the bottom of the active window.
HOME	Display the top of the active window.
NUM LOCK+ASTERISK on numeric keypad (*)	Display all subfolders under the selected folder.
NUM LOCK+PLUS SIGN on numeric keypad (+)	Display the contents of the selected folder.
NUM LOCK+MINUS SIGN on numeric keypad (-)	Collapse the selected folder.
LEFT ARROW	Collapse current selection if it's expanded, or select parent folder.
RIGHT ARROW	Display current selection if it's collapsed, or select first subfolder

Tell your Experinece about using shortcut keys of keybord.And share your experinece.

Accessibility keyboard shortcuts

Press	To
Right SHIFT for eight seconds	Switch FilterKeys on and off.
Left ALT +left SHIFT +PRINT SCREEN	Switch High Contrast on and off.
Left ALT +left SHIFT +NUM LOCK	Switch MouseKeys on and off.
SHIFT five times	Switch StickyKeys on and off.
NUM LOCK for five seconds	Switch ToggleKeys on and off.
+U	Open Utility Manager.

Natural keyboard shortcuts

Press	To
	Display or hide the Start menu.
+BREAK	Display the System Properties dialog box.
+D	Show the desktop.
+M	Minimize all windows.
+Shift+M	Restores minimized windows.
+E	Open My Computer.
+F	Search for a file or folder.
CTRL+ +F	Search for computers.
+F1	Display Windows Help.
+ L	Lock your computer if you are connected to a network domain, or switch users if you are not connected to a network domain.
+R	Open the Run dialog box.
	Display the shortcut menu for the selected item.
+U	Open Utility Manager.

Dialog box keyboard shortcuts

Press	To
CTRL+TAB	Move forward through tabs.
CTRL+SHIFT+TAB	Move backward through tabs.
TAB	Move forward through options.
SHIFT+TAB	Move backward through options.
ALT+Underlined letter	Carry out the corresponding command or select the corresponding option.
ENTER	Carry out the command for the active option or button.
SPACEBAR	Select or clear the check box if the active option is a check box.
Arrow keys	Select a button if the active option is a group of option buttons.
F1	Display Help.
F4	Display the items in the active list.
BACKSPACE	Open a folder one level up if a folder is selected in the Save As or Open dialog box.

General keyboard shortcuts

Press	To
CTRL+C	Copy.
CTRL+X	Cut.
CTRL+V	Paste.
CTRL+Z	Undo.
DELETE	Delete.
SHIFT+DELETE	Delete selected item permanently without placing the item in the Recycle Bin.
CTRL while dragging an item	Copy selected item.
CTRL+SHIFT while dragging an item	Create shortcut to selected item.
F2	Rename selected item.
CTRL+RIGHT ARROW	Move the insertion point to the beginning of the next word.
CTRL+LEFT ARROW	Move the insertion point to the beginning of the previous word.
CTRL+DOWN ARROW	Move the insertion point to the beginning of the next paragraph.
CTRL+UP ARROW	Move the insertion point to the beginning of the previous paragraph.
CTRL+SHIFT with any of the arrow keys	Highlight a block of text.
SHIFT with any of the arrow keys	Select more than one item in a window or on the desktop, or select text within a document.
CTRL+A	Select all.
F3	Search for a file or folder.
ALT+ENTER	View properties for the selected item.
ALT+F4	Close the active item, or quit the active program.
ALT+Enter	Displays the properties of the selected object.
ALT+SPACEBAR	Opens the shortcut menu for the active window.
CTRL+F4	Close the active document in programs that allow you to have multiple documents open simultaneously.
ALT+TAB	Switch between open items.
ALT+ESC	Cycle through items in the order they were opened.
F6	Cycle through screen elements in a window or on the desktop.
F4	Display the Address bar list in My Computer or Windows Explorer.
SHIFT+F10	Display the shortcut menu for the selected item.
ALT+SPACEBAR	Display the System menu for the active window.
CTRL+ESC	Display the Start menu.
ALT+Underlined letter in a menu name	Display the corresponding menu.
Underlined letter in a command name on an open menu	Carry out the corresponding command.
F10	Activate the menu bar in the active program.
RIGHT ARROW	Open the next menu to the right, or open a submenu.
LEFT ARROW	Open the next menu to the left, or close a submenu.
F5	Refresh the active window.
BACKSPACE	View the folder one level up in My Computer or Windows Explorer.
ESC	Cancel the current task.
SHIFT when you insert a CD into the CD-ROM drive	Prevent the CD from automatically playing.

Data Communication All possible Terminologies

Try  to explain itself check your concept

Modems Standards

Traditional modems

   

56k Modems

Uploading

Downloading

Result

Lecture 1

Cable Modems

Downloading

Uploading

Electromagnetic Energy

Classes of Transmission Media

Transmission Media:

Guided

Unguided

Two classes of Transmission Media

Guided Media

Unguided Media

Guided Media

Guided Media:

Twisted-Pair cable

Coaxial cable

 Fiber-optic cable

Twisted pair cable:

Unshielded Twisted Pair UTP

Shielded Twisted Pair (STP)

Frequency range for twisted pair cable

100Hz                               5MHZ

Unshielded Twisted Pair (UTP)

Parallel Flat Wire

Noise Effect on Twisted-Pair

Advantages of UTP

Categories of UTP Cable

Category 1

Category 2

Category3

Category4

Category5

UTP Connectors

Lecture # 2

Shielded Twisted Pair (STP)

 Coaxial   Cable

Frequency Range of Coaxial

Coaxial cable

100 kHz 500 MHz

Coaxial Cable standards

Coaxial Cable Connectors

T-Connector

Terminators

Optical Fiber

The Nature of Light

Refraction

Example of Refraction

Direction of Refraction

Critical Angle

Critical Angle

Refraction

Optical Fibers & Reflection

Propagation Modes:

Mode

Multimode     Step-index          Graded-index

Single Mode

 Multimode Fiber

Disadvantage of Multimode Step-index Fiber

Multimode Graded-index Fiber

Lecture # 3

  Single Mode Fiber

  Fiber Sizes

Light Sources for Optical Cable

LED:

LASER:

Fiber Optic connectors

Advantages of Optical Fiber

Noise Resistance:

Less Signal Attenuation

Higher Bandwidth

Disadvantages of Optical Fiber

Cost

Installation

Disadvantages of Optical Fiber

   Fragility

 Unguided Media

Radio Frequency Allocation

Propagation of Radio Waves

Types of Propagation:

Space

TROPOSHERE

IONOSPHERE

Surface Propagation

Troposphere Propagation

Line-of-Sight

Broadcast

Ionosphere propagation

Line of Sight propagation

Space Propagation

LECTURE # 4

Propagation of Specific Signals

         

Very Low Frequency (VLF)

3 kHz                  Long-range radio navigation                30 kHz

Low Frequency (LF)

30 KHz             Long-range radio navigation                  300 KHz

Middle Frequency (MF)

                                                     AM radio

300 KHz               535 KHz 1.605 MHz 3 MHz

High Frequency (HF)

                                                                   CB radio

3MHz                                                                                    30Mhz

Very High Frequency   (VHF)

               Paging           TV      FM            Aircraft                TV

30MHz                     54        88      108                        174               216          300MHz

Ultra High Frequency   (UHF)      

                    Mobile Telephone                           UHF TV                             Cellur ra   paging                                                                                                                                    Microwave   3Ghz.

  300 MHz                                      470                                     806 

Super High Frequency (SHF)

                                          Microwave

  3GHz                                                                                     30Ghz

Extremely High Frequency (EHF)

                       Microwave             

30 GHz                                                       300GHz.

Terrestrial Microwave

       Repeaters

       Antennas    

   

      

        Parabolic Dish

         HORN

Satellite Communication

  Geosynchronous Satellite

 

Satellite Frequency Bands

Cellular Telephony

   Each service area is divided into small ranges called cells.

   

Operations of Cellular Telephony

Transmitting

Receiving

Handoff

Transmission Impairments

  Impairment

    Attenuation

    Distortion

     Noise

    

Attenuation

Decibel (dB)

Distortion

                             LECTURE # 5

Transmission Impairments

       Impairment:

        Attenuation

         Distortion

          

          Noise

Attenuation

Decibel (dB)

Distortion

Noise

Induced Noise

Crosstalk:

Impulse Noise

Performance of Medium:

  Throughput

   Propagation Speed

   Propagation Time

Throughput

Propagation Speed

Propagation Time

WAVELENGTH

Shannon Capacity

Media comparison

Cost:

Speed:

ATTENUATION:

EM Interference:

SECURITY:

Lecture # 6

Introduction to Multiplexing

Multiplexing

Path:

Channel:

Categories of Multiplexing

Multiplexing

Frequency-division multiplexing    (FDM)

Time-Division multiplexing (TDM)          Synchronous                       Asynchronous

Wave-division multiplexing (WDM)

FDM

FDM (Guard Bands)

GURD BANDS

DEMULTIPLEXING

Wave Division Multiplexing (WDM)

Mechanism of WDM

PRISM

TDM

Implementation of TDM

Synchronous TDM

Synchronous TDM Example

Synchronous TDM Frames

Interleaving

Weakness of Synchronous TDM Figure

  Demultiplexing Process

Framing Bits

Synchronous TDM

                                       LECTURE # 7

Bit Stuffing

Asynchronous TDM

Advantages of Asynchronous TDM

Asynchronous TDM Figure 1

Asynchronous TDM Figure 2

Asynchronous TDM Figure 3

Aspects of Asynchronous TDM

    Addressing and Overhead

Inverse Multiplexing

 Why do we need inverse Multiplexing?

Multiplexing Application

The Telephone System

                             LECTURE # 8

Telephone Services

Services

Analog services

Digital Services

Common Carrier Services & Hierarchies

Analog Services

Switched Analog Services

Analog Leased Service

Conditional lines

Analog Hierarchy

Digital Services

Types of Digital Services

Digital Services

Switched/56                         DDS                        Ds

Swithced/56 service

Digital Data Service (DDS)

Digital Signal (DS)     Service

T Lines

LECTURE # 9

T  Lines

T Lines for Analog Lines

T1 Frame (Figure)

Fractional T Lines (Figures)

E-Lines

Fiber to the Curb (FTTC)

FTTC in Telephone Network

FTTC in Cable TV Network

ERROR DETECTION AND CORRECTION

Introduction

                   Types of Errors

ERRORS

Single-bit

Burst     Errors

Error Detection  

Redundancy

Types of Redundancy checks

Vertical Redundancy check (VRC)

Performance of VRC

                           Lecture # 10

Error Detection and Correction Methods

Longitudinal Red Check (LRC)

Performance of LRC

Cyclic Redundancy check (CRC)

Qualities of CRC

The CRC Generator

The CRC   Checker

Polynomials

Selection of a Polynomial

Popular polynomials for CRC

Performance of CRC

                                 LECTURE #  11

Error Detection and Correction Method

Checksum

One’s Complement

CHECKSUM Generator

Cecksum Figure

Performance of Checksum

ERROR CORRECTION

   Single-bit Error Correction

Lecture#  12

   Hammming Code

  

    Redundancy Bits (r)

    Haming code

     Data Link Layer

      Introduction

      Data Link Layer & Its Functions

     Data Link Control

      Line Discipline

     Flow Control:

     Error Control:

     Line Discipline:

     Ways to do Line Discipline

      Enquiry/Acknowledgment (ENQ/ACK)

      Poll /Select

  

LECTURE # 13

Line Discipline

Enquiry/Acknowledgement (ENQ/ACK)

How it works?

Poll/Select

Polling

SELECTING

Addressing

Select

Poll

Flow Control-Definition

                      LECTURE #  14

    Flow Control        stop-and-wait             sliding window

     Flow Control-Explanation

     Flow   Control-Buffer

      Methods for Flow Control

     Stop and wait

      Advantages of stop and wait

            Simplicity

           

     Disadvantages of Stop and wait

          

          INEFFICIENT (slow)

             

          Sliding window

         

        AUTOMATIC REPEAT REQUEST (ARQ)

       Categories of Error Control

     Error control

   

Stop-and-wait                               Sliding window

     ARQ                                              

                                                GO-Back-n                    Selective-reject             

      

Stop and wait ARQ

Damaged Frame

Lost Frame       

               

Lost ACK, NAK Frame

    

        

                                     LECTURE #  15

SLIDING WINDOS ARQ

 Go Back n ARQ

  Go Back n-Damaged Frame

 Go Back n-Lost Data Frame

Go Back n-Lost ACK

Selective Reject ARQ

Selective Reject ARQ vs.  Go Back n

Protocols

Protocol

Protocol in Data Comm.

Data Link Protocols:

Categories of Data Link Protocols

Data Link protocols

     Asynchronous                                     Synchronous

        Protocols                                             protocols

\

Asynchronous Protocols:

Synchronous protocols:

Asynchronous Protocols

Inherent Slowness is a disadvantage:

 Not Complex and Inexpensive to implement

    Different Asynchronous Protocols

XMODEM

Transmission in XMODEM

  Control Frames in XMODEM

 Control Frames in XMODEM

  Control Frames from the receiver

      -ACK: Acknowledgement

       -NAK:  Error or Start of transmission

       -CAN:  Aborts the Transmission

         

                           LECTURE #  16

YMODEM

 ZMODEM

BLAST

KERMIT

Synchronous Protocols

Classes of Synchronous protocols

Character-Oriented Protocols

Bit-Oriented Protocols

Binary synchronous Communication (BSC)

CONTROL FRAMES

DATA FRAMES

DATA FRAMES

Data Frame with Header

Multiblock Frame

Multi

Frames

Control Frames

                        LECTRUE # 17

               

 

Bit-Oriented Protocols

SDLC      HDLC          LAPs               LANs

High Level Data Link Control (HDLC)

Characterization of HDLC

STATION TYPES (1)

STATION TYPES (2)

Primary station

STATION TYPES (4)

Combined station

Configuration (1)

Configuration (2)

Unbalanced configuration

Configuration (3)

Symmetrical Configuration

Configuration (4)

Balanced Configuration

Station Types & Configurations

Modes

Normal Response Mode (NRM)

Asynchronous Response Mode (ARM)

Asynchronous Balanced Mode (ABM)

HDLC Frames

1-Frames

S-Frames

U-Frame

Flag Field

HDLC Address Field

HDLC Control Field

P/F bit

HDLC  Control Field –EXTENDED

Piggybacking

 Link Access Procedures

LECTURE#  18

Local Area Network

Architectures for LANs

LAN compared with OSI

Logical Link control (LLC)

Medium Access Control (MAC)

PROJECT 802

IEEE 802.II

LLC

MAC

Protocol Data Unit (PDU)

DSAP and SSAP

CONTROL

ETHERNET

IEEE 802.3 define two categories

Access Method: CSMA/CD

Need for Access Method

COLLISIONS

Carrier Sense Multiple Access with collision Detection (CSMA/CD)

NA       CSMA        CSMA/CD

CSMA/CD

CSMA

Addressing

Data Rate

Implementation

10 Base 5: Thick Ethernet

Size limitations of 10 Base 5

Topology of 10 Base 5

RG-8 Cable

TRANSCEIVER

AUI Cables

TRANSCEIVER TAP

VAMPIRE TAP

                LECTURE #  19

Ethernet

802.3             Baseband Digital (Manchester)        Broadband Analog(PSk)

10Base 2: Thin Ethernet Advantages

Disadvantages

Physical Topology of 10 base 2

NIC

RG-58 Cable

BNC-T

10 base T: Twisted pair Ethernet

1 Base 5: STAR LAN 

DAISY CHAINING

Switched Ethernet

Fast Ethernet

 100 Base-TX and 100 Base-FX

100 Base-T4

Gigabit Ethernet

Token Bus

LECTURE #  20

Token Ring

Access Control of Token Ring

  Monitor stations

Token Ring Frame

Data Frame Fields

Implementation

Token Ring Switch

Multi station Access Unit (MAU)

FDDI

FDDI Time Registers

FDDI Timers

Station procedure

Dual Ring (Figure-1)

Dual Ring (Figure-2)

LECTURE #  21

Internet

Connecting devices (Figure-I)

Connecting devices (Figure-2)

Repeaters (Figure-I)

Repeaters (Figure-2)

Repeaters (Figure-3)

 Bridges

TCP/IP Protocols

Good luck for your future

if you have passion about data communication take further advance courses 

like CCNA .CCNP .