Topic 1B: Introduction to communication systems

Nota:

• Topic 1B

1. Common communication errors
   1. Factual errors
   2. Errors of tone of message
   3. Spelling and punctuation
   4. Consequences of poor communication are: Loss of public confidence, the cost of correcting the message and the cost of publishing the correct message.
2. Manual and computer based systems
   1. Methods of organising a manual filing system
      1. Alphabetical order, this is useful because you only need to search for the name of the customer
      2. Chronological order, you could store letters by date they were sent
      3. Classification, documents can be stored according to the topic they're about.
      4. Benefits and drawbacks of a manual filing system: It's easy to control access because data is stored in a physical place, manual documents can last a long time. However manual systems take up lots of space, you need to make back-up copies, risk of damage and once removed the document has to be returned.
   2. Computer based systems
      1. The benefits of this system are: More than one user can access the information at the same time, You can make copies of documents, less storage space is needed, it can be very quick to search for documents, it can be easy to edit documents and you can view the documents remotely.
      2. The drawbacks of this system are: You can easily delete data, need for security systems, cost of maintaining the system and the system needs to be well designed.
3. Input devices and output devices,
   1. Keyboards can be used to: enter text or input commands into the computer.
   2. Mice are pointing devices used to enter commands into a computer.
   3. Touch screen devices combine both a computer screen and a keyboard.
   4. Computer monitors
      1. Cathode Ray Tube, very old technology however they have a high-quality image.
      2. Plasma screen monitors, these have a long display life and a high quality image.
      3. Liquid Crystal Display, these are very thin, don't generate very much heat, and have a high screen resolution.
      4. Data projectors, these are very cheap, portable however they're expensive to replace, dangerous if looked directly at and only work best in dark places.
   5. Printers
      1. Inkjet printer, these are low cost and good quality but are slow and use loads of ink.
      2. Laser printer, These are expensive, but the cost per page is less and good quality with a good print time.
      3. Thermal printer, These are cheap and fast however the documents produced don't last very long and cannot create complex images.
      4. Dot matrix printer, these are very noisy and the print quality is low, but they are low cost.
4. Computing devices
   1. Desktop computers
      1. These usually consist of input devices such as: mouse, keyboard and scanner. Output devices such as: monitor, printer
      2. Desktop computers need software such as Windows and application software such as word processing software that creates text based documents.
      3. These usually have: a computer case, a CPU, a main memory, a long term memory and video and sound cards,
      4. There are benefits to these desktops: files and programmes can be stored in a central location, hardware can be shared and it is possible to use any machine on a network. The drawbacks are: the network is at risk from unauthorised users and if there is a problem with the network then everything is at risk.
   2. Laptops
      1. Benefits
         1. They're portable
         2. They're small
         3. They can use the same applications as a computer
         4. They have wireless internet
      2. Drawbacks
         1. Fragile
         2. They can get lost or stolen easily
         3. If one component becomes damaged then the hole laptop may need to be replaced.
         4. Laptops are less powerful
   3. Handheld devices
      1. Being so small, they're easy to lose or break, they're not very powerful and can be fiddly to use
      2. They're light and small, They're easy to store and can be used anywhere
5. Storage devices
   1. Hard disks: These have a large memory capacity and can locate a specific piece of data very quickly however they're fragile and can be damaged.
   2. Magnetic tape: this has a very large memory capacity at cheaper price than other forms of storage. However it can take a long time to locate a specific item of data on the tape.
   3. Portable flash drives: They have a small size and large memory capacity, so they can be used to transfer large volumes of data. However they can be used to steal important data and are easy to lose or can be damaged.
   4. Optical disks: These can be in the form of, CD-ROM where data cannot be deleted, CD-R this allows the user to burn data to them and CD-RW where the user can add and delete data.
6. Data security
   1. Threats to computers
      1. Viruses: these are programmes designed t disrupt the workings of a computer.
      2. Spyware: this software is designed to monitor the ways a computer is used then reports it back to someone.
      3. Adware: this software is designed to display adverts based on your searching habbits
      4. Phishing: where people pretend to be companied they're not, such as banks asking you to re-enter your password.
   2. User precautions
      1. Never open an email attachment unless you're certain what it contains.
      2. Be careful when visiting websites
      3. Never give out your personal data.
      4. Always make sure that computer safety software is switched on and used.
      5. Never leave your computer unattended while logged on.
   3. Protection methods
      1. Make sure that all activity on your computer is monitored by anti-virus software, anti-spam software, anti-spy software and anti phishing software.
      2. Firewalls, these monitor any incoming and outgoing traffic from the computer.
      3. Encryption: this protects data whilst it is being transferred between two computers
7. E-commerce
   1. Benefits
      1. Shopping can be done from home.
      2. Shopping can be done at any time of the day.
      3. Home delivery
      4. A wider choice is available
      5. Cheaper prices
   2. Drawbacks
      1. Delivery charge and long times to deliver.
      2. Payment details must be kept safe.
      3. Customers must trust the company.
   3. Benefits to a business: They can reach customers all over the world, it is easy to update the details on a website, the business can employ fewer staff, the business can use surveys to communicate with customers and gather feedback
   4. Drawbacks to a business: They need to make sure that the website is kept safe from unauthorised users, the website must be kept up to date and the business must make sure that it can cope with the number of visits to the website.