Transmitting and Receiving by Alyce Muldoon and Sarah Bryant

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					What aqe the pqocessoqs?
The other processors include:
☻ Collecting


☻ Organising ☻ Analysing ☻ Storing and Retrieving ☻ Processing ☻ Transmitting and Receiving ☻ Display

Come On All Students Pat The Dog!

What is Tqansmitting and Receiving?
☺Transmitting and receiving is the information process that involves the transfer of data and information from within and between information systems.

☺Example of transmitting and receiving for both noncomputer and computer systems include emails, radio, telephones, roads, walkie talkies, and faxes.
☺Communication concepts, hardware, software, noncomputer tools and social and ethical issues relating to transmitting and receiving.

☺Types of digital data transmission, serial and parallel transfer ☺Serial transfer transmits data through a single line one bit at a time

☺Parallel transfer transmits data using separate lines and more then one bit of data at a time.

☺ Parallel transfer is used inside the system unit and for connecting peripheral devices e.g. a printer ☺ Serial transfers are used for connecting peripheral devices e.g. modems, it is used over longer distances using cables such as telephone lines. ☺ Serial transmissions can be broken into two different parts.
☺ One: asynchronous transmission, which is when each byte has special start and stop bits attached to them. ☺ Two: synchronous transmission, which is a transmission which requires all the bits to be sent at the same rate. It is much faster and more efficient.

☻ Direction of the flow of data can be three different modes. Simplex, half duplex or full duplex
☻ Simplex mode:- transmission can only flow one way

☻ Half duplex:- transmission to flow both ways but not at the same time
☻ Full duplex mode:- transmissions can flow both ways at the same time

☺ Hardware includes modems and networks as well as the internal components of the computer ☺ Pathway of wires which provides the link between input, storage, process and output devices is known as a bus

☺ The size of it is known as the width ☺ Two different types of buses include internal and expansion.

☻ Internal buses link the CPU and memory, and expansion buses connect peripheral devices to the CPU and memory ☻ Two types of ports, parallel and serial.
☻ Modems allow data to be transmitted from one computer to another ☻ modulator/demodulator

☻ A network is like what is set up in our school now. It is a number of computers all connected

• Communications software manages the transfer of files and commands between computers using a set of rules that governs the transfer of data between the computers known as a protocol to establish a connection. Two computers must have the same protocol or the data transfer maybe unsuccessful. There are many different protocols for networks the most popular are Ethernet and Token Ring.
• Compression reduces the number of bits required to represent data. Data is compacted to take up less space on a disk and requires less downloading time. In order to extract the original information, compressed data must be decompressed. File compression is measured by compression ratio and is either lossy or lossless.

• Electronic mail (email) is communication with other users by sending and receiving electronic messages using a computer. Messages are written offline and sent when the user logs onto the LAN (local area network) or the internet. Attachments are computer files sent with email messages, such as image, audio, video or text files. • Data encryption is prevention from data being intercepted and read during transmission. The data is scrambled to become meaningless to anyone but the recipient who will convert it back. A popular method is Secure Socket Layer (SSL).

• The mail system allows you to send a letter or package to an address anywhere around the world. Mail delivery relies on road, rail and air transportation systems. Though mail systems have improved with technology in machines and faster methods of postal handling and delivery.
• The telephone system transmits sound or speech between distant places along telephone wires. The telephone relies on a receiver being available to accept a phone call.

• Fax machines transmit and reproduce documents by means of signals sent over telephone lines. Fax machines scan documents and convert them to a bit mapped image. This image is compressed and transmitted along the telephone network to the destination fax machine. The machine decompresses the image and converts it to a bit mapped image.

•Radio is the transmission and detection of sound using electromagnetic waves that travel through the air. When a radio receiver is tuned to the frequency of a radio station, a signal is received. Radio allows people to receive up-to-date information and entertainment. This form of radio is restricted to one way transmissions of data. • Television is the transmission and detection of images and sound using electromagnetic waves that travel through the air. A scene to be televised is converted into a sequence of electrical pulses that are transmitted via an antenna. The television translates the electrical pulse into a corresponding sequence of images and sounds that are displayed via the screen and speakers. To achieve rapid motion smoothly it is necessary to transmit 25 to 30 complete pictures per second. Normal television is a one way transmission of data but digital television has become an interactive medium (two way).

☺ The accuracy of information published on the internet it not guaranteed as it is so easy to publish information their. For this reason data should be compared with a number of sources.

☺ The security of data transferred over the internet is a greater problem then data stored on a single computer. One way to protect data from deliberate or accidental damage is the use of a certificate. A certificate or digital signature is an encrypted code to ensure that unauthorised people cannot access data.
☺ ‘Netiquette’ refers to the way people communicate to each other over the internet. It is about being considerate of other users and thinking about the consequences of your actions. It is about using appropriate behaviour when sending emails, chatting or using news groups. ☺ Acknowledgement of sources is necessary when downloading data. Data obtained from the internet is protected by copyright. To quote an internet source it is important to note the author’s name, title of the work, URL of the page and date of downloading day.

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