Communication Flashcards
Bit
The smallest unit of data in a computer
Bit rate
The rate at which data is transferred
Serial transmission
Uses a single wire to transfer data
Parallel transmission
Uses multiple wires to transfer data
Interference
Disturbances that corrupt data; occurs when transmitting data
Skew
When different buses/lines in parallel transmission arrive at different times
Crosstalk
When different buses/lines in parallel transmission interact with each other, creating unwanted data changes
Simplex transmission
Sending data in only one direction (radio/TV)
Duplex transmission
Sending data in both directions at the same time (phone)
Half-duplex transmission
Sending data in both directions but only one at a time (walkie-talkie)
Checksum
Error detection method. The number of bits being transmitted is counted up and the numeric count is transmitted with the data. If the counts match then the receiver knows that the right number of data has been transmitted, but individual errors are not detectable
Parity check
Error detection method. A parity bit at the end of a byte is used to make the bits add up to an odd or even result, depending on the type of parity used (odd or even). The sender and the receiver agree on which type of parity is to be used, and if the parity bits match on both ends then the receiver knows that the bits add up to the same type of number
Check digit
Error detection method. All of the numbers are added up and the result is added at the end. If the numbers match on both ends then the receiver knows that the number is correct
Automatic repeat request
When the receiver detects an error, it sends a request to the sender to resend the packet. It will keep requesting new packets until a correct packet is received or the limit of requests is reached
WAN
Wide area network
ISP
Internet service provider. It is a company that provides us with access to the internet, for a fee
Browser
A program that allows a user to visit, retrieve, and display the information that a website contains.
HTML
The language that websites are written in. It consists of the content, and the instructions on how to interpret said content.
URL
Uniform resource locator. It is made up of the access protocol (HTTP/HTTPS) and the domain name (e.g. google.com)
Cookie
Tiny pieces of data that are downloaded by a computer when visiting a website. It is used to keep track of things, and the website accesses the cookies stored on the computer whenever the client visits it
Internet protocol
Governs transmission of data via the internet. HTTP (hypertext transfer protocol) or HTTPS (hypertext transfer protocol over secure) is used
IP address
Internet protocol address. 32 bit code, broken down into four groups of 3 digits. Is an address just like a house address - it is used to identify different devices connected to the internet. Can be static (doesn’t change) or dynamic (held for a certain period of time)
MAC address
Media access control address. 48 bit code, broken down into 6 pairs of two-digit hexadecimal numbers. Unique to each device, is given by the manufacturer and cannot be changed
