INFO 2 CH18 - Use of Communications Technologies

Allows users to create profiles and communicate with other users. Users can invite people and friends to a little network so they can communicate privately to everyone. There are hundreds of social media sites for connecting people together. The user can share personal information about themselves and pictures which all their friends can see and read about. 

They can keep in touch with friends, exchange information and share links. Additional software can be added that offers a peer-to-peer service that allows a user tos hare or stream media.

A dial – up allows connectivity to the internet through a standard telephone line. While the user is connected to the modem on the computer they cannot make standard telephone calls. It is also much slower than a broadband connection. The users are charged by the amount of time they use the internet. 

Asymmetrical Digital Subscriber Line (ADSL)

It uses the copper standard telephone line to retrieve fast broadband while still using the telephone line for calls. You have to pay for a monthly subscription and they are available in different speeds and download. 

As most internet users recieve a lot of data and only send emails, ADSL is an attaractive option and cheaper than dedicated fibre-optic cables. It is not suitable when a user needs to send data at high speeds. 

Cable

It is available in lots of towns and cities across the country. It is only available in areas where fiber optic cable for TV is installed. However it is expensive to install the fiber optic cable and viable in high populated areas.  The upload speeds Is slower than the download speed. 

Wireless

Uses secure radio signals instead of a phone line. It is available in certain areas of the country. Sparsely populated places have better use of the wireless because if they are out of reach from local exchanges and broadband. 

Large business need to be careful when setting up a peer to peer network. User accounts need to be ste up and maintained with appropriate access rights. File servers for software and data and access to the internet with adequate security measures need to be put in place. 

Electronic Data Interchange  (EDI)

EDI is a means of transferring information such as invitations to tender, letter, orders and invoices electronically. It allows the computer in one organization to “Talk” to the computers in their suppliers organistaion, regardless of computer manufacturer or software type. EDI collects the orders directly from one company’s computer and sends them to the supplier’s computer. 

Electronic Mail(Email)

It is very easy to send and receive electronic messages to or from any other person or organistation that has an email address. They can send emails all around the world for the same cost as accessing the internet. It is a very efficient means of communication. It saves time and the cost of postage. These emails can include attachments like photos documents videos. The disadvantages of this is that if it is from span, unreliable source there could be a virus that transfers to the recipients computer when the attachment is opened. 

Fax

Arrives quickly like email, but it gives a hard copy. It is short for Facsimile Transmission. It uses telephone lines to transmit copies of an originally document. It scans the document, encodes the contents and transmits them to another fax machine which decodes and prints off a copy of the original. It takes longer to send then a file because it’s a graphical image.

Teletext – no longer exists

ELECTRONIC information service which can be viewed on most televisions. The user has to pay extra for it. It is operated through the TV remote. Can be used to view the news, weather and TV schedules. It is cheap and easy to use. They have stopped it because everyone now has internet and it was faster than teletext.

Videoconferencing

Sometimes called teleconferencing means being able to see and interact with people who are graphically apart. To do it you would need a webcam so the other user can see you. A headset consisting of a microphone and earphones so you can speak to the other users and so you can hear what they are saying using a VoIP software. The equipment can sometimes be expensive and the quality of the images are not that good. 

Forums 

Is an online discussion group. Users with common interests can exchange messages that can be read by everyone who is currently accessing the forum. On the internet the forum is called a newsgroup. To view and post messages to a newsgroup, you need a news reader, a program that a user’s runs on his computer. It connects to a news server on the internet.

A network may be restricted to one room or one building or cover a small geographical area. Such an area is called a Local Area Network (LAN). A LAN was traditionally connected via direct lines - pysical links using its own dedicated cables. These can be Twisted wire, Coaxial or Fibre-optic cable. The development of wireless networks means that many small LANs now operate without physical cables. Small, home networks where several computers are linked using a wireless router were discussed earlier. Many small businesses use a peer-to-peer local area network where resources can be shared easily.

A network may be spread over a wide geographical area, possibly covering different countries. Such a network is called a Wide Area Network (WAN). It can be linked by public telecommunications systems. The internet is a very large WAN. Many large organisations have their own server-based local area network linked into a WAN.

Very extensive networks exist which are often called Metropolitan Area Networks (MAN). 

Standards 

If you bought a new computer system, you would expect to be able to transfer data from your old machine. If you bought a more recent software version, you would expect it to be able to read data from the previous version. If you bought a digital camera, you would expect to be able to transfer the images to your PC. You can expect these things because standards are in place.

Hardware Standards

Today most computers have a number of USB (Universal Serial Bus) ports, which are used to connect a wide range of peripherals. This equipment must conform to standards, which means that buyers are no longer restricted to one company. Competition means cheaper prices for the buyer.

Software Standards

The use of software standards should make applications easier use by having a common feel. Software can usually save work in a variety of different formats which enable portability and compatibility.

A protocol is a set of formal rules and procedures that define how devices can communicate. Without protocols there would be no agreed way in which a computer could transfer data to and from another computer. 

Protocols enable the use of open systems - computer systems that can communicate regardless of the manufacturer and the platform. This is very important for the Internet, which can be accessed by a wide variety of hardware devices. 

The internet uses a number of internationally-agreed standards and protocols which mean that it can be accessed by a variety of hardware platforms. 

The standards ensure that there is a reliable connection between devices and provide error detection and correction mechanisms. The following protocols are used on the Internet:

File Transfer Protocol (FTP) - Allows a file to be transferred from one computer to another; it is often used to upload files to the Web.

HyperText Transfer Protocol (HTTP) - Is a standard for transferring web pages to a client computer. 

Post Office Protocol (POP) - Is a standard for transferring email between computers.

Transmission Control Protocol/Internet Protocol (TCP/IP) - Allows Internet users and providers to communicate with each other, no matter what hardware is used.

Wireless Application Protocol (WAP) - Is a standard for wireless communication networks used by mobile phones to access the Internet.

The main advanatge of standards is that user is not restricted to one manufacturer's equipment. Even if one company's computers are all the same make, they may wish to communicate with another company whose hadware is different. This would not be possible without protocols. Being able to choose from a variety of manufacturers means there is competition and prices are likely to be lower.

The main disadvantage of standards and protocols is that they are difficult to change. It is difficult and takes time to get universa; agreement on the establishment of new standards. 

• They are difficult to change
• They may not be able to keep up with the new technology
• The full power of the machine might not be available

De Jure Standards

Many standards are formally introduced, often after considerable deliberation by an international committee. These are called De Jure standards and include:

• ASCII codes were devised by the American Standard Code of Information Interchange
• The JPG image format was developed by the Joint Photographic Experts Group (JPEG), which represents a wide variety of companies and academic institutions worldwide.
• Most Internet protocols, such as TCP/IP, were drawn up by CERN (the European Organisation for Nuclear Research, an international group of 20 member countries based in Geneva, Switzerland)

De Facto Standards 

Other standards, known as De Facto standards, arise through historic precedence or as a result of marketing and sales successs of a particular product. Examples of De Facto standards include:

• MS-DOS and Microsoft Windows have become the standard operating system and GUI for PCs
• The GIP image format was created in 1987 by Internet company CompuServe as a format for transmitting images over the internet.
• RSS is used for the sgaring of Web content. Its most widespread use is in distributing news headlines on the Web.

Often De Facto standards have evloved not because they are technnically the best but due to commercial or other pressured.