4.9.1.2 Communication basics Flashcards
What is baud rate?
The number of signal changes per second - rate at which signals change
How can baud rate be lower than bit rate?
More than one bit can be encoded in each signal change
Bit rate = baud rate * number of bits per signal change
What is bit rate?
The rate at which data is transferred, the number of bits. It is measured in bits per second, the higher the bit rate, the higher the quality and the larger the file.
What is bandwidth?
The range of frequencies that can be transmitted
What is the relationship between bandwidth and bit rate?
Directly proportional - the greater the bandwidth the higher the bit rate
What’s the difference between broadband and baseband?
Baseband is where the whole of the bandwidth is dedicated to one channel at a time meaning only one computer can send data at a time. This is useful for LANs because it’s lower cost as it’s simpler hardware.
Broadband is where bandwidth is shared over multiple channels so many computers can send data. It’s useful for WANs because it’s more expensive to maintain but more cost effective because more computers can be connected.
What is latency?
The delay between an action being instigated and its effect being noticed
What does a modem do?
Translates digital signals into analogue and vice versa
What is a protocol and why is it needed?
A set of rules to allow communication between devices
