3.5 Communication Technologies (Fax/VoIP/VC) Flashcards
Describe how facsimile machines work.
They make a digital copy of an image or text which is fed into the machine. The image is then transmitted to another fax machine via a telephone line. The receiving fax then prints an image based on reconstructing the signals coming in.
What does a fax machine consist of?
A printer and optical scanner.
What is required for a computer to send faxes? Why?
A fax modem - the protocol for transmitting faxes is different to that for transmitting digital data.
State 5 disadvantages of fax machines.
- Must be connected to a telephone line, can be interrupted by telephone calls if not connected to a dedicated fax line
- Operate mostly in black and white
- Expensive to buy
- Expensive to run due to toner cartridges, electricity charges and cost of telephone calls
- If the receiving fax machine is not free to receive the document, it will have to be resent
Describe VoIP.
Voice over Internet Protocol - makes telephone calls over the internet.
• VoIP software, telephone/headset needed
• Calls can be made from PC to phone or from PC to PC
• Cheaper than through a telephone company because it makes use of broadband connection
• Eg Skype
Describe video conferencing.
Communicating on a network using sound and pictures. A high bandwidth telecommunications line is necessary to ensure the quality of the conference.
List the equipment needed for video conferencing.
- Video camera / webcam
- Microphone and sound system
- Screen
- High bandwidth telecommunications line
- Voice conferencing software
State 4 advantages of video conferencing.
- No travel costs for the company
- Collaborate with members without having to leave your desk
- No travel time for employees
- Visual and audio contact means more realistic meetings
State 4 disadvantages of video conferencing.
- High cost for initial setup
- Specialist training may be required to make use of a purpose-built VC system
- Network performance may be poor when VC is in operation
- High bandwidth required
Describe instant messaging.
Allows users to use text to communicate instantly with each other. When a user types a message, all of the users logged in can see the message instantly.
Describe bulletin boards.
Provide text-based messaging but is not instant or interactive. When a user logs on to a bulletin board and posts a message, it may be a few hours or days before a reply is posted.
