Parallel vs Serial Communications
Parallel
- Port has 8 data wires
- Large series of ground and control wires
- Examples
- PCI expansion ports
- Hard-disk connectors
Serial
- Single data wire or single differential pair
- Other wires are ground or control wires
- Examples
- USB
- SATA
- PCI Express
Network Definitions
Bandwidth
- The amount of data that can be passed over a communication channel over a specific period of time
Bit-rate
- The amount of data that is transferred in a second, measured in bits.
Baud rate
The rate at which the number of signal elements or changes to the signal occurs per second when it passes through a transmission medium.
The higher the baud rate the faster the data is sent/received.
Simplex
- Communication channel that sends data in one direction only
Half Duplex
- Simplex
- But the direction can be reversed
Duplex
- A point to point system made of two or more devices in a network that can communicate in both directions
How changing x effects network performance
Bandwidth
- The amount of data that can be transmitted through a communication channel.
- Bandwidth = upper frequency - lower frequency
Bit rate
- Higher bit rate results in faster speeds
Baud rate
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Higher baud rate results in higher speeds.
-
The baud rate is the number of times per second that the electronic state of a channel can change.
-
Bit rate = baud rate x number of bits per signal
Simplex
- Faster but less reliable
- Simplex is one way transmission
Duplex
- Slightly slower but more reliable
- Data can flow in both directions at once
ADSL—Why do you never get advertised speeds?
- On an ADSL setup, you don’t get a dedicated connection. The connection speed advertised is shared between multiple properties, so if you have several different people using the internet from different households, they all use some of the ADSL connection’s resources.
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