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Difficulty: MediumDisplay Cables and Connectors

An IT technician is attempting to connect an older legacy computer with only a DB-15 (VGA) output port to a newly installed monitor that features only an HDMI input port. The technician connects the two devices using a passive VGA-to-HDMI adapter cable, but the monitor displays a "No Signal" message. Which of the following best explains the reason for this issue?

  1. VGA outputs an analog signal, whereas HDMI requires a digital signal; a passive cable cannot convert signal formats without an active powered converter.Answer
  2. B
    The resolution setting on the legacy computer exceeds VGA bandwidth limits and must be lowered to 640x480 before a passive cable can pass video.
  3. C
    The host system lacks a Thunderbolt controller, which is required for passive video adapter cables to negotiate DisplayPort Alternate Mode.
  4. D
    VGA connectors carry digital signals that fail unless the monitor supports High-bandwidth Digital Content Protection (HDCP) over legacy wiring.

Answer

VGA outputs an analog signal, whereas HDMI requires a digital signal; a passive cable cannot convert signal formats without an active powered converter.
VGA outputs an analog signal, while HDMI requires a digital signal. A simple passive cable only changes the connector pin arrangement; it lacks the electronic components required to digitize an analog signal into an HDMI-compatible digital signal. To connect an analog VGA source to a digital HDMI display, an active converter box powered via USB or external power is required.

Step-by-Step Solution

1
Identify the video output signal type of the computer port.
The DB-15 (VGA) port generates an analog video signal.
VGA is a legacy standard that transmits separate analog RGB voltage signals.
2
Identify the video input signal type of the monitor port.
The HDMI port requires a digital video signal.
HDMI relies on Transition-Minimized Differential Signaling (TMDS) digital streams.
3
Determine adapter requirements for signal conversion.
An active converter with a digital-to-analog or analog-to-digital processing circuit powered externally is required.
Passive adapter cables only reroute pins and cannot perform signal processing or digitization.

Key Concept

Passive vs. Active Video Signal Conversion (Analog VGA to Digital HDMI)
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Topics

Display Cables and Connectors

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