Networks & Communications

Node
A node is a "connection point" in a network. It is either the distribution point or the end point of for data transmissions. A node is programmed to transfer, process as well as receiving transmissions to/from the other nodes. The modem, router, hub, or bridge is made up of a programme of network nodes .

Client
A client is a browser where a user requests for pages from the servers across the web. In other word, a Client is a system that accesses a remote service on server. Clients are also classified under 3 main categories, they are Fat Client, Hybrid Client, and Thin Client.

Server
A server is a programme running in a computer that handles requests for browsers. At the same time, they provide services for their users from other computers. Also, any devices or computers sending out information or services can be called as a Server. A server is famous for its use to host online games or LAN games.

Hub
A hub is a connection point between the devices in a network. A hub contains multiple ports that are used to connect the Segments in a LAN. They also connect multiple twisted pair or fibre optic Ethernal devices together so that they could work as a single network segment. There are 3 main types of hubs, a passive hub, a active hub, and an intelligent hub.

Below is a diagram of a client-server.

Network Interface Card (NIC)
It is an expansion board that users insert into the computer system so that the computer can connect to the network. It is usually called NIC or a network card. Most NICs are designed for a particular type of network, protocol, and media.
an expansion board you insert into a computer so the computer can be connected to a network. The card communicates with the central wireless switch or hub via radio waves.

Below is an image of a Network Interface Card (NIC)

Network Operating System (NOS)
A NOS is a system that connects the computer and devices to the LAN. The system supports workstation, personal computer, and also some older terminals. Some example of NOSs are Netware and Microsoft LAN's Manager. They provide printer sharing, common file system, and also database sharing as well as application sharing. Also, they have the ability to manage a network name directory and also its security.

Distributed Processing
Distributed Processing means that a computer system uses more than one computer or processor to run applications. An example is the parallel processing in which a computer contains more than 1 CPU to execute its programmes. Most of these systems contain sophisticated software that detects idles on the network and then parcels out programmes to solve them.

Below is an image of a Distributed Processing, where a computer uses more than 1 processor/CPU to run its applications.

Host Computer
A Host Computer is a computer that is attached to a network, and then provides services like acting as a store-and-forward processor or communication switch. It acts as the main computer connected to the other computers to which it provides data or computing services via a network. It is very similar to a Server.

Network Manager
It is also known as the Network Administrator. It is a software ultility aimed at simplifying the uses of computer networks. Also, it ensures the network's security, performances and also the reliability. It works by collecting counterparts and data for LAN Network Manager. It is developed by Microsoft in cooperation with 3Com Corporation.

Input and Output

Magnetic Ink Character Recognition (MICR)
It is a character recognition system that uses specialized ink, symbols and characters which can be magnetised and read automatically and then be printed out rapidly. It is widely used in banks to print the details on cheques. Reason being the magnetic-ink character can be read under greater accuracy. Each character will produce an unique waveform that can be easily identified only by the computers.



Image of an MICR Reader



Image of the codes and characters






Optical-character Recognition (OCR)
It is a computer-science that reads text from papers and translate the image into a form of data that the computer can manipulate. For example, you can take 1 page of article from a hardcopy and transfer it into datas to computer system for further editting using a word software or etc. I.e: Optical Scanner
Advanced OCR can read text in many types of fonts. However there are still difficulties in reading handwritten texts.


Image of an OCR Reader






Optical-mark Recognition (OMR)
It is a technology where data is extracted electronically from check boxes, fill-in fields, on printed forms. Different from an OCR, a recognition engine is not required. Therefore, this will require the image or text to have higher contrast so that it can be easily recognized. This technology is very fast and can be used in a variety of application. I.e, business reply mail, surveys, verification of signatures.



Image of an OMR Reader



Image of a form




Dot Matrix Printer
It is a kind of printer that produces characters or illustrations by strinking pins against an ink ribbon, to print the closely-spaced dots to produce characters. These kind of printers are expensive and do not produce high quality output. However, they can print multiple pages forms that sometimes a bubble-jet printer or laser printer cannot do. The Dot Matrix Printer is measured in 2 different characteristics that are the speed and the print quality.



Image of a Dot Matrix Printer and its output character.




Plotters
It is a kind of printer that interprets commands from a computer to make line drawings and adjustments on paper with an automated pen. It can also draw contineous point-to-point lines from graphic files. The operating rate is very slow because of the mechanical movement of the drawing pens. They can produce high resolution vector-based outputs as well as creating very large drawings.



Image of a Plotters





Photo Printer
A photo printer is usually the printer that is designed to produce high quality digital photographs. These printers usually contain a lot of nozzles that are used to spray printing droplets as small as 1 picoliter. Unlike standard inkjet printers, photo printers can print images that is taken directly from the camera that supports the PictBridge protocol. Popularity of this printer has increased over the extensive use of digital cameras.


Image of a Photo Printer




Portable Printer
This kind of printers are small, light and portable. They are designed for travellers or those who needs to work while "on the go". This design is aiming at its conveniency of digital photography. Travellers can just snap a photo, plug the camera in to the printer, and then print them out straight away in very fine quality.


Image of a Portable Printer connected to a Digital Camera.





Fax Machine
It is a device that can send and receive text or images over a telephone line. It functions by dividing the text medium into little grid of dots. Each dot is represented by the bit that has a value which is 1(off) or 0(on). The "Off" and "On" determinds the output colours whether they are in black or white. A series of codes translated by the system into readable data are called a "bit map". On the receiving side, they receive the data and translate them back into human-readable images or text and then print them out.



Image of a Fax Machine





Multifunctional Devices
It is the kind of printers that are designed for greater working efficiency. The functions of scanning, copying, printing and faxing are clamped together into one printing device so that it allows user to save money on other compartments. This kind of printers can help users to save space too. The price of these printers are low and affordable, but the performances are good enough because it can perform a huge range of multifunctional colour printings.



Image of a Multifunctional Devices





Internet Telephones
An Internet Telephone service uses the Internet instead of the traditional phone lines to send voice over the receiving end(s). Phone lines are plugged into the computer and users can communicate via the headphone that is plugged into the USB slot. This Internet Telephone service can help to save money and at the same time allows the customer to enjoy better calling features and qualities. The calls can be extremely cheap or even free to anywhere in the world.


Image of an Internet Telephone connected with the USB cable.





Telephony
It is a technology associated with the electronic transmission of voice, fax and other information between long distant parties using a handheld device containing both speaker and transmitter as well as a receiver. It contains the function of sending voice messages along with text e-mails. Fax transmissions can also be sent at a very low cost.


Image of a Telephony Network



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