Dot Matrix Printing

Dot Matrix Printing

Dot matrix printing or impact matrix printing  is a type of computer printing which uses a print head that moves back-and-forth, or in an up-and-down motion, on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper, much like the print mechanism on a typewriter.

A type of printer that produces characters and illustrations by striking pins against an ink ribbon to print closely spaced dots in the appropriate shape. Dot-matrix printers are relatively expensive and do not produce high-quality output. However, they can print to multi-page forms (that is, carbon copies), something laser and ink-jet printers cannot do.





Dot-matrix printers vary in two important characteristics:

>> speed: Given in characters per second (cps),the speed can vary from about 50 to over 500 cps. Most dot-matrix printers offer different speeds depending on the quality of print desired.




>> print quality: Determined by the number of pins (the mechanisms that print the dots), it can vary from 9 to 24. The best dot-matrix printers (24 pins) can produce near letter-quality type, although you can still see a difference if you look closely.

Internet

INTERNET

• The Internet is a global network of interconnected network, enabling users to share information along multiple channels.
• A computer that connects to the Internet can access information from a vast array of available servers and other computers by moving information from them to the computer’s local memory.
• A majority of widely accessible information on the Internet consists of inter-linked hypertext documents and other resources of the World Wide Web (WWW).
• Computer users typically manage sent and received information with web browsers; other software for users’ interface with computer networks includes specialised programs for electronic mail, online chat, file transfer and file sharing.
• The movement of information in the Internet is achieved via a system of interconnected computer networks that share data by packet switching using the standardised Internet Protocol Suite (TCP/IP).
• It is a “network of networks” that consists of millions of private and public, academic, business, and government networks of local to global scope that are linked by copper wires, fiber-optic cables, wireless connections, and other technologies.
• It is really a way for computers to communicate and share informations.
• It is a fast developing net and is of outmost importance for public sector undertakings, educational institutions, research organisations etc.

Services of Internet

E-mail

• The internet enables user to exchange data/information and communicate via electronic media.
• E-mail messages are usually encoded in American Standard Code for Information Interchange (ASCII) text.
• A popular protocol for sending e-mail is Simple Mail Transfer Protocol (SMTP) and for receiving it is POP3.

Chat

• It is the exchange of typed message by netizens.
• It enables netizens to ‘talk not vocal’ by typing and sending the messages back and forth.
• It has two modes—computer to telephone and computer to computer.
• Internet Relay Chart (IRC) developed by Jarkko Oikarinen in 1998.

Video Conferencing

• A service that allows a group of users to exchange video information over the internet.
• It include an audio teleconference facility.
• Each participant’s computer must have a camera, microphone and earphones (or speaker).

Stylus Pen

Stylus Pen

In computing, a stylus (or stylus pen) is a small pen-shaped instrument that is used to input commands to a computer screen, mobile device or graphics tablet. With touchscreen devices, a user places a stylus on the surface of the screen to draw or make selections by tapping the stylus on the screen.

To insert a function from the Function Library

To insert a function from the Function Library:

In our example below, we'll use a function to calculate the number of business days it took to receive items after they were ordered. In our example, we'll use the dates in columns B and C to calculate the delivery time in column D.

1. Select the cell that will contain the function. In our example, we'll select cell D3.
   
2. Click the Formulas tab on the Ribbon to access the Function Library.
3. From the Function Library group, select the desired function category. In our example, we'll choose Date & Time.
4. Select the desired function from the drop-down menu. In our example, we'll select the NETWORKDAYS function to count the number of business days between the ordered date and received date.
   
5. The Function Arguments dialog box will appear. From here, you'll be able to enter or select the cells that will make up the arguments in the function. In our example, we'll enter B3 in the Start_date: field and C3 in the End_date: field.
6. When you're satisfied with the arguments, click OK.
   
7. The function will be calculated, and the result will appear in the cell. In our example, the result shows that it took four business days to receive the order.
   

• Like formulas, functions can be copied to adjacent cells. Hover the mouse over the cell that contains the function, then click, hold, and drag the fill handle over the cells you want to fill. The function will be copied, and values for those cells will be calculated relative to their rows or columns.
  

The Function Library

The Function Library

While there are hundreds of functions in Excel, the ones you use most frequently will depend on the type of data your workbooks contains. There is no need to learn every single function, but exploring some of the different types of functions will be helpful as you create new projects. You can search for functions by category, such as Financial, Logical, Text, Date & Time, and more from the Function Library on the Formulas tab.

• To access the Function Library, select the Formulas tab on the Ribbon. The Function Library will appear.

Click the buttons in the interactive below to learn more about the different types of functions in Excel.

TYPES OF SCANNER

Types of Scanner

1. Flatbed Scanners
2. Sheet-Fed Scanners
3. Integrated Scanners
4. Drum Scanners
5. Portable Scanners
6. Handheld Scanner