What modulation mode is used for ADSL access in MA5600 products?

Question

Options

• ADMT
• BPMT
• CCAP
• DAAL5

• A
  76% (31)
• B
  12% (5)
• C
  7% (3)
• D
  5% (2)

Explanation

DMT (Discrete Multi-Tone) is the standardized physical-layer modulation technique for ADSL, splitting the available frequency spectrum into up to 256 sub-carriers, each independently modulated - this is what Huawei's MA5600 DSLAM implements. PMT is not a recognized ADSL modulation standard and serves as a pure distractor. CAP (Carrierless Amplitude and Phase modulation) was an early proprietary ADSL approach that lost to DMT when ITU-T standardized ADSL (G.992.1), so while it is a real technology, it is not what MA5600 uses. AAL5 (ATM Adaptation Layer 5) is a data-encapsulation protocol at the link layer, not a modulation scheme at all - it describes how packets are framed over ATM, not how bits are encoded onto the copper line.

Memory tip: DMT = Discrete Multi-Tone, many tones across the spectrum. If you picture a piano keyboard where each key is a separate sub-carrier, you have DMT - and ADSL is that piano.

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