Communication Technologies and Their Uses

Fax machine scans a page to make an electronic representation of its
text or graphics, compresses the data to save transmission time, and
transmits it to another fax machine. The receiving machine decrypts the
signal and uses a printer  to make a facsimile of the original page.

This procedure is often applied in interlace scanning which helps to reduce flick (as it involves more number of views in the picture per second ) in the received image without increasing the channel bandwidth.

Fax machine makes an exact copy of a document made by electronic scanning and transmitted as data by telecommunications links.

True. A modem is a device or program that enables a computer to transmit data over.

Cybernetics is the interdisciplinary study of the structure of regulatory systems, focusing on control and communication in both living organisms and machines.

IP stands for Internet Protocol. The Internet Protocol (IP) is the principal communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet.

IP has the task of delivering packets from the source host to the destination host solely based on the IP addresses in the packet headers

The Advanced Research Projects Agency Network (ARPANET) was an early packet switching network and the first network to implement the protocol suite TCP/IP. Both technologies became the technical foundation of the Internet. 

DSL (Digital Subscriber Line) is a technology for bringing high- bandwidth information to homes and small businesses over ordinary copper telephone lines. xDSL refers to different variations of DSL, such as ADSL, HDSL, and RADSL.

HTML stands for Hyper Text Markup Language and is a syntax for representing text and images in a web browser. Using this syntax, a web page can be designed

Standard toolbar consist of buttons that helps us to browse the files using internet

Transferring files from a computer to the internet is known as uploading, while the opposite , i.e transferring files from internet to computer is known as downloading

Menu bar is kept below the title bar and has many options like File, Edit, View, Favourites, etc

Escape button in the keyboard plays an analogous role to the STOP button in the browser and stops the activity of the browser 

Title bar in a browser displays the name of the program

HOME button in a browser refers to the first webpage in that particular site

The Refresh button in the web browser helps one to reload a website.

The STOP button in a web browser is designed to interrupt the loading process of a webpage, which is useful if a page is taking too long to load or if the user decides they no longer wish to view it.

Clicking the edit button helps one to edit the complete website

A website is defined as a collection of related webpages, which are documents accessible via the World Wide Web, typically identified by a common domain name.

The first commercial ISP used is the world and it started at USA . Its first customer was served in November 1989

An ISP provides the users services for accessing, using or participating in the internet

Google , Yahoo and Bing are search engines, while Windows is an operating system

Scroll bars aid in moving through a website horizontally or vertically

Status bar in a website will depict the status of the current work (loading a website) that is being done 

The amount of data in a multimedia application runs for a few Giga bases and hence storage cost and its processing cost increases. This is one of the disadvantages of using multimedia

The address of the website , also known as URL should be typed in an address bar, while the find and search dialog boxes will be useful only in searching the text in a given file

World Wide Web (WWW) is the fastest growing part of the internet. This constitutes a collection of resources used for a variety of purposes such as computing, browsing, searching, etc and can be accessed by a software known as BROWSER

ARPANET is the first network used to implement TCP/IP protocol, while the rest of them are ISPs

There are numerous advantages (as well as disadvantages) to conducting an interview online rather than face-to-face. These include practical factors such as the lower cost and greater convenience of conversing electronically, the opportunity it gives respondents to compose careful answers that say exactly what they want to say, and the elimination of transcription error.

Online focus groups can be conducted either synchronously or asynchronously. In the former case, the researcher can use conferencing software to help participants converse in real time, although this can be problematic if some participants do not have access to the software. (A possible modern remedy for this might be instant messaging services.) Asynchronous focus groups can be conducted via an email distribution list, allowing people more time to compose their responses. However, a problem with this is that the moderator cannot be available online whenever someone is writing a message, and so it can be harder to keep the discussion on track and check the content of messages before they are posted.

While the Internet can be an extremely useful resource for recruiting research participants, the samples that result are likely to be biased towards certain social groups. This is because Internet users tend to be disproportionately young, middle class, and wealthier and so these characteristics will be over-represented in the sample as compared to the general population.

Computer-mediated communication provides some great opportunities for distributing a social survey to a relatively large sample of respondents. The researcher can either send their questionnaires out via email, provide a web-link in an e-mail, or they can present the survey on a website, where people are invited to complete it online.

The Internet can be used as a valuable source of quantitative and qualitative data, but there are limitations to this technique of data collection. The researcher's sample of websites will depend on the keywords they used to search for them, and of course websites are prone to being revised, updated and even removed over time. However, there are plenty of websites out there in cyberspace!

The internet originated from ARPANET, a project funded by the U.S. Department of Defense, with the primary goal of creating a decentralized network that could remain functional even if parts of the network were destroyed in a disaster.

Online surveys can be sent via email, either embedded in the body of the message or as a separate attachment. The advantage of the latter is that it allows the researcher to use more embellishments and formatting to make the survey look attractive, which in turn may improve the response rate. However, some people may have technical difficulties in opening the attachment, or they may be too worried about computer viruses to risk doing so.

VSNL is a global service provider of telecommunications solutions and services. Now it is a part of Tata group and this was the first ISP who provided internet facility to India
The rest of them are ISPs, which are currently being used as ISPs 

There is a growing tendency for researchers to administer questionnaires through more than one medium. Thus they might send out a printed copy of the questionnaire by post to everyone in the sample, but explain in the covering letter that the survey can also be found online, for example at a web site. This allows recipients of the letter to choose whether to respond by post or online, and so it has the potential to improve the study's response rate. Meanwhile, there is growing evidence that using online questionnaires alone produces a lower response rate than postal surveys. It seems that Internet users have become quite sophisticated in their attitudes to unsolicited emails. Spam filters and security software may inadvertently trash some messages, particularly those with attachments. 

High bandwidth is available for transmission in LANs as compared to WANs

An internet address (domain name) must contain the name of the organization or entity, followed by a top-level domain (like .com, .org, or .gov) to be valid and reachable.

Internet is a set of rules to communicate between computers

A router acts as the gateway between a local network and the internet; therefore, configuring its security settings (like firewalls and access controls) is the most effective way to protect all computers within a WAN from external hacking.

LAN Experiences fewer data transmission errors, while WAN has more data transmission errors as compared to LAN

Every computer connected on the network should have an unique address, and this address is known as IP address

Through the internet, we can remotely login a device easily, transfer files and mail someone but word processing doesn't require internet facility it is already there as a application software.

In LAN, If there is a need to set-up a couple of extra devices on the network, it is not very expensive to do that and hence cost associated to setup a LAN is less

For WANs since networks in remote areas have to be connected the set-up costs are higher. 

An intranet is a private network that uses internet protocols (like TCP/IP) and web technologies to share information and resources within an organization, restricted to authorized users.

Packet-switched describes the type of network in which relatively small units of data called packets are routed through a network based on the destination address contained within each packet. Breaking communication down into packets allows the same data path to be shared among many users in the network. This type of communication between sender and receiver is known as connectionless (rather than dedicated). Most traffic over the Internet uses packet switching and the Internet is basically a connectionless network.

While a meaningful address and feedback features are helpful, help and search facilities are considered essential for usability, allowing users to navigate large amounts of content effectively.

The bandwidth used to transmit telephone signals is very low , it is generally around $4 KHZ$ in range .So, the quality of audio signals is low , therefore make it difficult to recognize the speaker's voice .

The basic component of a transmitter are.

The frequency range provided is typically allocated for narrow-band communication, which is sufficient for voice signals but lacks the bandwidth required for high-fidelity music or video (TV) signals.

Photocell are used for the conversion light to frequency signals. So, In television the light from T.V camera is converted to video frequency signals that are further processed

ISD is International Subscriber Dialing . It is placing an international telephone call that is dialed directly by a telephone Subscriber , rather than by a telephone operator .

The infrared radiation of low frequency are used in remote control handset of T.V .The low powered infrared waves make sure the signals sent from your remote does not penetrate the walls and interfere with outside surroundings .

Cellphone and radio works the same way. Cellphone can be said as a two way radio as both the sender and receiver can send audio signals simultaneously while in radio only audio signals are sent one way from sender to receiver .

The mouthpiece has a mic that converts the audio waves  from our voice to electric signals , that are carried further away to receiver .

Mobile phones are called two way radio devices as the communication is done the same way as Radio , but here both the sender and receiver can send information at the same time simultaneously . Unlike the radio;s where only sender can send the information and receiver will receive it at a moment of time

A mobile phone can be used to send voice and text message .Also it can be used as a mini computer due to increasing processor's power these days and the communication between any two persons can be done even if they are moving .

$\boxed{T.V. Camera}$

Fax machine scans a page to make an electronic representation of its text or graphics, compresses the data to save transmission time, and transmits it to another fax machine. The receiving machine decrypts the signal and uses a printer  to make a facsimile of the original page.

In a full-duplex system, both parties can communicate with each other simultaneously. An example of a full-duplex device is a telephone; the parties at both ends of a call can speak and be heard by the other party simultaneously.

Television relay centers require long-distance, high-bandwidth transmission methods. Microwave links, booster relays, and satellites are standard components used to transmit television signals across large distances.

The World-Wide Web Worm (WWWW) is the first search engine for the World-Wide Web, though it was not released until March 1994, by which time a number of other search engines had been made publicly available.

It was developed in September 1993 by Oliver McBryan at the University of Colorado. The worm created a database of 300,000 multimedia objects which could be obtained or searched for keywords via the WWW. In contrast to present-day search engines, the WWWW featured support for Perl regular expressions.

Scroll button can be used to view any website of variable width or height. The website can be even for 2 or 3 pages, scrolling down helps an user to view the page completely, just like turning the pages of a notebook

Virtual focus groups have some advantages, such as making it easier for shy or reticent people to participate in the relatively anonymous setting of an online discussion. However, the method also has numerous disadvantages that stem from this lack of face-to-face interaction: it is more difficult to build rapport online and so the researcher may find it harder to prevent people from dominating the discussions, ignoring questions or dropping out of the study altogether.

A Local Area Network (LAN) is defined by its limited geographic scope, typically confined to a single building or campus, where computers are connected to share resources like files, printers, and internet access.

Both HTML and XML are derived from SGML (Standard Generalized Markup Language), which provides the framework for defining markup languages.

A Document Type Definition (DTD) or an XML Schema is required to define the structure, elements, and attributes allowed in an XML document, enabling parsers to interpret the data correctly.

All data transfers across the Internet work on this principle. It helps networks manage traffic -- if one pathway becomes clogged with traffic, packets can go through a different route. This is different from the traditional phone system, which creates a dedicated circuit through a series of switches. All information through the old analog phone system would pass back and forth between a dedicated connection. If something happened to that connection, the call would end.

That's not the case with traffic across IP networks. If one connection should fail, data can travel across an alternate route. This works for individual networks and the Internet as a whole. For instance, even if a packet doesn't make it to the destination, the machine receiving the data can determine which packet is missing by referencing the other packets. It can send a message to the machine sending the data to send it again, creating redundancy. This all happens in the span of just a few milliseconds.

A WAN consists of two or more LANs. The computers are farther apart and are linked by telephone lines or radio waves. Eg: Internet

Information transmitted through internet is broken down in terms of small units of data called packets and are routed through a network based on the destination address contained within each packet. Breaking communication down into packets allows the same data path to be shared among many users in the network. This type of communication between sender and receiver is known as connectionless (rather than dedicated). Most traffic over the Internet uses packet switching and the Internet is basically a connectionless network.

As the transmission of television is done through satellite's . So, the carrier waves should be of high frequency , so , the carrier waves should be of high frequency , so that they may clear the Ionosphere and provide a smooth transmission  between a satellite and television set