Communication Systems Flashcards
An address book in email is used for what purpose?
Used to store people’s email address and contact details
Advantage of Teleconferencing
It reduces costs by simulating face-to-face meetings.
Asynchronous transmission must insert……
a start bit before each data character and a stop bit at its termination to inform the receiver where it begins and ends.
Most network protocols (such as Ethernet, SONET, Token Ring) use synchronous transmission whereas asynchronous transmission is used commonly for communications over telephone lines.
Audio conferencing or Teleconferencing is what?
A single phone call involving 3 or more people at different locations.
Describe Bandwidth
The Bandwidth is the capacity of the channel, or transmission medium. It’s how much data can travel along the medium.
The Baud Rate is….
The maximum number of data symbols or electrical signals that can be transmitted in one second
Bits per Second (bps) is….
The maximum number of bits that can be transmitted in one second.
Bits per second in relation to a communication setting is….
The speed of transmission
What is a Blind carbon copy (Bcc)
A copy of an email that is sent to other people, but they can’t see who else got it (optional)
Define a Bus Topology
All the devices are attached to a direct line called the bus. Nodes listen if the network is clear. If so, a node will transmit. If collision occurs, Carrier Sense Multiple Access and Collision Detection (CSMA/CD) allows node to re-transmit at later time.
What is a Carbon copy (CC - email header component)
Send the same message to other people apart from the main recipient (optional)
Describe what Checksum is
An error checking method that counts the bits in a data packet. Data is divided into packets and the bits in each packet are counted and sent to the receiver. If the numbers match, it is assumed their is no error in the transmission.
Communication settings are…..
parameter settings that may be altered to allow computer or peripherals to communicate
Define a communication system.
An information system that enables people to send and retrieve data
Briefly define how Cyclic Redundancy Check (CRC) works
Binary numbers are divided by a number. The remainder of the division is retained & sent. Receiving computer re-does the calculation. If both agree, it is OK to send. Detects 99.99% of all errors.
What is a mail server?
The specific computer or server where a person’s emails are stored
What does EFTPOS stand for.?
Define what it is.
Electronic Funds Transfer at Point-of-Sale
EFTPOS is a system that allows people to purchase good and services. It electronically transfers money from the costumer bank account to the sellers bank account.
Electronic Commerce (e-commerce) is……
the buying or selling of goods through the internet. It is a type of communication system.
Electronic banking……
allows people to view and manage their own bank accounts online and transfer money between their own accounts, or to pay other people or bills online.
Electronic mail (email) is……..
the sending of mail electronically. It was revolutionised by the invention of the internet. Can be sent around the world in a matter of seconds/minutes and to anyone who has an email address.
What is an Email Address?
The address of the person who is receiving or sending emails. They are unique and comprise of two parts.
- The name / username of the person, and
- The domain name (computer /company location on the Internet).
They are separated by the @ symbol.
Describe the structure of an Email message.
An email has two main parts. The header and the body.
- The header is like an envelope.
It contains the email address of the person to whom the the email is going to, the subject of the email (a title that helps to explain what the email is about), and the sender’s email address, which is automatically added in order for the peron to be able to reply to the emial if need be. - The body is the main message
This is where the main message is conveyed to the receiver. It can be as long or as short as required. However, it is recommended to try and keep emails short and to the point.
Describe Half-Duplex Data Flow
The data flows both ways, but only one way at a time
Example = Walkie Talkies
Describe Full-Duplex Data Flow
The data flows both ways, both at the same time
Example = Telephone
Parallel transmission refers to……
transferring data at the same time using separate channels. It is faster, but gets out of sync easily.
Describe a Ring Topology
All devices are attached so that the path is in the shape of a continuous circle. Each device has a unique address. Data flows in one direction, moving from device to device until it arrives at destination. This avoids data collisions. A node transmits when it receives a token, hence the name, token ring network
Serial transmission…….
is transferring data one after another it is slower but less errors. Serial transmission can be asynchronous or synchronous
Describe Simplex Data Flow
The data flow is one direction (receives signal only)
Examples = Television, Radio,
Define a Star topology?
A star topology has a central computer with each device connected directly to it. The central computer acts like a switch and if it goes down, the whole network goes down.
List the 5 components of a communication system
- Source
- Transmitter
- Transmission Medium
- Receiver
- Destination
