200-301 Question 492
Single answerA network administrator is troubleshooting a communication issue between two devices on a wired Ethernet network. The administrator suspects that the issue lies in how the binary data is being converted for transmission over the physical medium. Which data encoding method would ensure that there are no long periods of no voltage change, which can help maintain synchronization between the devices?
- A
Non-Return-to-Zero (NRZ)
- B
Manchester Encoding
- C
4B/5B Encoding
- D
Pulse Amplitude Modulation (PAM)
Show answer and explanation
Correct answer: B
Explanation
Manchester Encoding is a data encoding method that ensures there is always a voltage transition for every bit, which helps maintain synchronization between sender and receiver. This is critical in scenarios where long sequences of identical bits could otherwise cause synchronization issues. Non-Return-to-Zero (NRZ) fails in such cases, while 4B/5B and PAM are unrelated to this specific problem.
- A. Incorrect.
Non-Return-to-Zero (NRZ) suffers from long periods of no voltage change when transmitting consecutive identical bits, such as multiple 0s or 1s, which can lead to synchronization issues.
- B. Correct.
Manchester Encoding ensures there is always a voltage change for every bit transmitted, even if consecutive identical bits are sent. This helps maintain synchronization between devices.
- C. Incorrect.
4B/5B encoding is used to map 4-bit data into 5-bit codes for transmission, but it relies on another encoding scheme (such as NRZI or Manchester) for physical signaling and doesn't inherently solve the issue of voltage changes on its own.
- D. Incorrect.
Pulse Amplitude Modulation (PAM) is a modulation method used for transmitting data over an analog signal and is not directly related to solving long periods of no voltage change in binary encoding.