What is the rated working voltage of the MA5600 equipment?

Question

Options

• A-24
• B-36
• C-48
• D-72

• A
  8% (3)
• B
  3% (1)
• C
  75% (30)
• D
  15% (6)

Explanation

Option C (-48V) is correct because -48V DC is the global telecommunications industry standard for powering access network equipment, including Huawei's MA5600 MSAN/DSLAM platform. This negative voltage convention was established by the Bell System to reduce electrolytic corrosion on copper lines and has been maintained across virtually all carrier-grade equipment ever since.

Why the distractors are wrong:

• A (-24V) is too low for carrier-grade equipment; it's sometimes used in smaller embedded systems but not full-scale access nodes.
• B (-36V) is not a recognized telecom power standard - it falls between common battery plant voltages and is not used in practice.
• D (-72V) exceeds the standard; while higher voltages exist in some power distribution contexts, -72V is not a standard operating voltage for this class of equipment.

Memory tip: Think "-48 for the gate" - 48 is the standard telecom power voltage, and access equipment like the MA5600 sits at the "gate" between the core network and subscribers. If you remember one DC telecom voltage, it's -48V.

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