Common Network Terms

Node

In communication networks, a node which comes from the Latin word nodus, ‘knot' is a connection point, either a redistribution point or a communication endpoint (some terminal equipment). The definition of a node depends on the network and protocol layer referred to. A physical network node is an active electronic device that is attached to a network, and is capable of sending, receiving, or forwarding information over a communications channel.

Apassive distribution point such as a distribution frame is consequently not a node. In network theory or graph theory, the term node refers to a point in a network topology .

Client

A client runs on different computers interconnected by a computer network. A client sends the receiver a message by the network, hence the client managers local resources such as a display, keyboards and local disks. an example of a client is a banking application that allows a clerk to access the account information on a central database server as it is an extension of the object-base program.

Sever

A server is an application running on a computer that delivers a service. For example, a web server will deliver web pages when requested by a browser (called client in this context). The way a server and a client dialogs is called a protocol. For instance, HTTP is the protocol used between a browser an a web server. Among the many services provided by the Internet servers are:
World Wide Web
the domain name system
e-mail
FTP file transfer
chat and instant messaging
voice communication
streaming audio and video
online gaming

Hub

A network hub or repeater hub is a device for connecting multiple twisted pair or fiber optic Ethernet devices together and thus making them act as a single network segment. Hubs work at the physical layer of the OSI model. The device is thus a form of multiport repeater. Repeater hubs also participate in collision detection, forwarding a jam signal to all ports if it detects a collision.
Hubs also often come with a BNC and/or AUI connector to allow connection to legacy 10BASE2 or 10BASE5 network segments. The availability of low-priced network switches has largely rendered hubs obsolete but they are still seen in older installations and more specialized applications.

Network Interface Cards

A network interface controller (NIC) is a hardware device that handles an interface to a computer network and allows a network-capable device to access that network. The NIC has a ROM chip that contains a unique number, the media access control (MAC) Address that is permanent. The MAC address identifies the device uniquely on the LAN. The NIC exists on both the 'Physical Layer' and the 'Data Link Layer' of the OSI model.
Sometimes the words 'controller' and 'card' are used interchangeably when talking about networking because the most common NIC is the network interface card. Although 'card' is more commonly used, it is less encompassing. The 'controller' may take the form of a network card that is installed inside a computer, or it may refer to an embedded component as part of a computer motherboard, a router, expansion card, printer interface or a USB device.

Network Operating System

A networking operating system is an operating system that contains components and programs that allow a computer on a network to serve requests from other computer for data and provide access to other resources such as printer and file systems.

Distributed prossessing

Distributed processing implies that processing will occur on more than one processor in order for a transaction to be completed. In other words, processing is distributed across two or more machines and the processes are most likely not running at the same time, i.e. each process performs part of an application in a sequence. Often the data used in a distributed processing environment is also distributed across platforms.

Host Computer

In computer networking, a network host, Internet host, host, or Internet node is a computer connected to the Internet - or more generically - to any type of data network. A network host can host information resources as well as application software for providing network services.
Every Internet host has one or more IP addresses uniquely assigned to the host. The addresses are assigned either manually by the computer administrator, or automatically at start-up by means of the Dynamic Host Configuration Protocol (DHCP).
Every host is a physical network node but not every physical network node is a host. Network devices such as modems and network switches are usually not assigned host addresses, and are not considered hosts. Devices such as network printers and hardware routers are assigned IP addresses, but since they are not general-purpose computers, they are sometimes not considered as hosts.

Network Maneger

NetworkManager is a software utility aimed at simplifying the use of computer networks on Linux and other Unix-like operating systems.NetworkManager is designed in two components: a service which manages connections and reports network changes, and a graphical desktop applet which allows the user to manipulate network connections. Both components are intended to be reasonably portable, and the applet is available to desktop environments

INPUT and OUTPUT...

INPUT and OUTPUT

Magnetic Ink Character Recognition (MICR)

Magnetic Ink Character Recognition, or MICR, is a character recognition technology used by the banking industry to facilitate the processing of cheques. This technology allows computers to read information, such as account numbers off of printed documents. Unlike barcodes or similar technologies, MICR codes can be easily read by humans.


MICR characters are printed in special typefaces with a magnetic ink that usually contains iron oxide. As a machine decodes the MICR text, it first magnetizes the characters in the plane of the paper. Then the characters are then passed over a MICR read head, a device similar to the playback head of a tape recorder. As each character passes over the head it produces a unique waveform that can be easily identified by the system.The use of magnetic printing allows the characters to be read reliably even if they have been overprinted or obscured by other marks, such as cancellation stamps.

Optical-Character Recognition (OCR)

Optical character recognition, or usually know as OCR, is the mechanical or electronic translation of images of handwritten, typewritten or printed into machine-editable text. OCR is a field of research in pattern recognition, artificial intelligence and computer vision. Though academic research in the field continues, the focus on OCR has shifted to implementation of proven techniques. Optical character recognition and digital character recognition were originally considered separate fields. Because very few applications survive that use true optical techniques, the OCR term has now been broadened to include digital image processing as well.

Optical-Mark Recognition (OMR)

OMR is generally distinguished from optical character recognition by the fact that a complicated pattern recognition engine is not required. That is, the marks are constructed in such a way that there is little chance of not reading the marks correctly. This does require the image to have high contrast and an easily-recognizable or irrelevant shape. A related field to OMR and OCR is the recognition of barcodes such as the UPC bar code found on product packaging.In contrast to the dedicated OMR device, desktop OMR software allows a user to create their own forms in a word processor and print them on a laser printer. The OMR software then works with a common desktop image scanner with a document feeder to process the forms once filled out.

Dot Matrix Printer

The dot matrix printer or impact matrix printer is a type of computer printer with a print head that runs 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 a typewriter. Unlike a typewriter, the letters are drawn out of a dot matrix, and thus, varied fonts and arbitrary graphics can be produced. Because the printing involves mechanical pressure, these printers can create carbon copies and carbonless copies.


ach dot is produced by a tiny metal rod, also called a "wire" or "pin", which is driven forward by the power of a tiny electromagnet or solenoid, either directly or through small levers (pawls). Facing the ribbon and the paper is a small guide plate (often made of an artificial jewel such as sapphire or ruby) pierced with holes to serve as guides for the pins. The moving portion of the printer is called the print head, and when running the printer as a generic text device generally prints one line of text at a time.

These machines can be highly durable. When they do wear out, it is generally due to ink invading the guide plate of the print head, causing grit to adhere to it; this grit slowly causes the channels in the guide plate to wear from circles into ovals or slots, providing less and less accurate guidance to the printing wires. Eventually, even with tungsten blocks and titanium pawls, the printing becomes too unclear to read.

Plotters

A plotter is a vector graphics printing device to print graphical plots, that connects to a computer. There are two types of main plotters. Those are pen plotters and electrostatic plotters.Pen plotters print by moving a pen across the surface of a piece of paper. This means that plotters are restricted to line art, rather than raster graphics as with other printers. Pen plotters can draw complex line art, including text, but do so very slowly because of the mechanical movement of the pens. Pen Plotters are often incapable of creating a solid region of color; but can hatch an area by drawing a number of close, regular lines.

Photo Printer

A photo printer is a printer (usually an inkjet printer) that is specifically designed to print high quality digital photos on photo paper. These printers usually have a very high number of nozzles and are capable of printing droplets as small as 1 picoliter.Photo printers have increased in popularity in recent years along with the increased use of digital cameras. Before this, photo printers were typically priced much higher than standard inkjet printers and were mostly used by professionals. Epson began to market photo printers to consumers with their Stylus Photo line. Soon after that, Canon began offering inexpensive photo printers and eventually all other major printer manufacturers followed.

Recently, the major printer manufacturers began releasing compact photo printers. These models print 4"x6" photos and do not require a computer. There are also larger format photo printers that are used to print on 8"x11", 10"x14" or larger photo paper. Mainly these larger format printers are manufactured by Canon, Epson or HP.

Portable Printer

A portable printer is where a portable hard disk drive connector with a parallel (printer) port control board including: a casing including an upper cover and a lower cover engaged with the upper cover; and a control board fixedly fitted in the lower cover and having a parallel (printer) port interface input connector partly protruding out the casing, a parallel (printer) port output connector partly protruding out of the casing, and a hard disk drive connector provided at its both ends with a rack thus forming a U-shaped frame for receiving a hard disk drive.

Fax Machine

The fax machine is a telecommunications technology used to transfer copies (facsimiles) of documents, especially using affordable devices operating over the telephone network. The word telefax, short for telefacsimile, for "make a copy at a distance", is also used as a synonym. Although fax is not an acronym, it is often written as “FAX”. The device is also known as a telecopier in certain industries. When sending documents to people at large distances, faxes have a distinct advantage over postal mail in that the delivery is nearly instantaneous, yet its disadvantages in quality have relegated it to a position beneath email as the prevailing form of electronic document transfer except where the legal status of a sent fax and its accompanying sending report are desired.

Multifunctional Devices

Multifunctional devices bring the worlds of copying, printing, finishing, and scanning together, all in one neat, efficient and cost-effective package. Therefore this machine which incorporates the functionality of multiple devices in one, so as to have a smaller footprint in a home . A typical MFP may act as a combination of some or all of the following devices:
Printer
Scanner
Photocopier
Fax
E-mail

Internet Telephones

Voice over Internet Protocol (VoIP) is a general term for a family of transmission technologies for delivery of voice communications over IP networks such as the Internet or other packetswitched networks. Other terms frequently encountered and synonymous with VoIP are IP telephony, Internet telephony, voice over broadband (VoBB), broadband telephony, and broadband phone.
Internet telephony refers to communications services — voice, facsimile, and/or voice-messaging applications — that are transported via the Internet, rather than the public switchedtelephone network (PSTN). The basic steps involved in originating an Internet telephone call are conversion of the analog voice signal to digital format and compression/translation of the signal into Internet protocol packets for transmission over the Internet; the process is reversed at the receiving end.

Telephony

The general use of this equipment is to provide voice communication over distances, specifically by connecting telephones to each other.

Telephones were originally connected directly together in pairs. Each user had separate telephones wired to the various places he might wish to reach. This became inconvenient when people wanted to talk to many other telephones, so the telephone exchange was invented. Each telephone could then be connected to other local ones, thus inventing the local loop and the telephone call. Soon, nearby exchanges were connected by trunk lines, and eventually distant ones were as well. digital technology in the provision of telephone services and systems. Almost all telephone calls are provided this way, but sometimes the term is restricted to cases in which the last mile is digital, or where the conversion between digital and analog signals takes place inside the telephone. Telephony was digitized to cut the cost and improve the quality of voice services, but digital telephony was then found useful for new network services (ISDN) to transfer data speedily over telephone