H19-410_V1.0 · Question #247
SDH basic transmission module is STM-4STM-1.
The correct answer is B. False. B (False) is correct because the basic transmission module of SDH (Synchronous Digital Hierarchy) is STM-1, not STM-4. STM-1 operates at 155.52 Mbit/s and serves as the fundamental building block from which all higher SDH rates are derived. Why A (True) is wrong: STM-4 is not…
Question
SDH basic transmission module is STM-4STM-1.
Options
- ATrue
- BFalse
How the community answered
(56 responses)- A16% (9)
- B84% (47)
Explanation
B (False) is correct because the basic transmission module of SDH (Synchronous Digital Hierarchy) is STM-1, not STM-4. STM-1 operates at 155.52 Mbit/s and serves as the fundamental building block from which all higher SDH rates are derived.
Why A (True) is wrong: STM-4 is not the basic unit - it is simply four STM-1 frames multiplexed together, running at 622.08 Mbit/s. It is a higher-order module, not the foundational one.
Memory tip: Think of the "1" in STM-1 as "first" or "fundamental." All other SDH levels (STM-4, STM-16, STM-64) are exact multiples of STM-1, so the number tells you how many STM-1s are combined - making STM-1 the undeniable base unit.
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