In digital communications and computer networking, the abbreviation PCM stands for what?

Introduction / Context:
Many technical abbreviations have historical meanings outside of personal computing. In telecommunications and signal processing, PCM is a foundational technique used to convert analog audio (such as voice) into a digital bitstream for storage or transmission. The question asks for the correct expansion among options that focus on PC-related phrases.

Given Data / Assumptions:

• We are in a networking/communications context.
• PCM’s standard expansion is a telecom term, not a PC vendor term.
• The listed options all reference “PC” or manufacturers, not signaling methods.

Concept / Approach:
PCM stands for Pulse Code Modulation. It involves sampling an analog signal at a fixed rate, quantizing the samples, and encoding them as binary numbers. Since none of the provided options offer “Pulse Code Modulation,” the accurate choice is “None of the above.”

Step-by-Step Solution:

Verification / Alternative check:
Telephony standards (for example, T-carrier, E-carrier) and audio formats reference PCM as Pulse Code Modulation, confirming the mismatch with the options.

Why Other Options Are Wrong:

Common Pitfalls:
Assuming abbreviations with “PC” are always about personal computers; many come from telecommunications where the meanings differ.

Final Answer:
None of the above