Why do some communication standards use 8b/10b encoding?

Question: Why do some communication standards use 8b/10b encoding?

 

Answer:

8B/10B encoding ensures the correct function of the link by providing the following:
- A minimum transition density to allow the serial receive PLL to extract a clock from the data stream.
- A DC-balance in the signaling to reduce data baseline wander
- Run-length limits in the serial data to limit the bandwidth of the serial link
- A means of framing the remote receiver