If the GPON optical module type is Class C+, how much value of its receiving sensitivity?

Question

Options

• A7dBm
• B3dBm
• C-32dBm
• D-12dBm

• A
  7% (1)
• B
  7% (1)
• C
  86% (12)

Explanation

Option C (-32 dBm) is correct because GPON Class C+ is defined by ITU-T G.984.2 as having a minimum receiving sensitivity of -32 dBm, meaning the receiver can detect signals as weak as -32 dBm - the highest sensitivity among standard GPON optical classes, enabling longer reach networks.

Why the distractors are wrong:

• A (7 dBm) confuses receive sensitivity with transmit power - 7 dBm is the maximum transmit output power for Class C+, not what it receives.
• B (3 dBm) is near the minimum transmit power range for Class C+ (+3 to +7 dBm); positive dBm values describe transmitting, not receiving sensitivity.
• D (-12 dBm) is too high (too weak a sensitivity) and doesn't correspond to any standard GPON class specification.

Memory tip: Receive sensitivity is always a large negative number (the receiver picks up faint, attenuated signals). Remember the pattern: higher class = more negative sensitivity. Class C+ is the "top class," so it has the most negative value: C+ = -32 dBm. Think "C+ students reach further" - Class C+ extends network reach by detecting the weakest signals.

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