Display / Audio-Video

HDMI

HDMI (High-Definition Multimedia Interface) is an audio/video interface for transmitting uncompressed digital video and compressed or uncompressed digital audio from an HDMI-compliant source device to a compatible display. It replaced older analog standards like VGA and component video for consumer electronics. HDMI carries both high-definition video and multi-channel audio through a single cable.

Primary Use

Digital Audio & Video Output

Reference Image

HDMI cable and connector

Key Features

  • Trapezoidal (wider on top) connector shape - distinctive and easy to recognize
  • 19 pins in the standard Type A connector
  • Carries both digital video AND audio in a single cable
  • Supports HDCP (High-bandwidth Digital Content Protection) copy protection
  • Hot-pluggable - can be connected/disconnected without powering off devices
  • Supports resolutions from 720p up to 10K (depending on version)
  • Supports ARC (Audio Return Channel) and eARC for sending audio back to receivers
  • CEC (Consumer Electronics Control) allows devices to control each other

Variants & Standards (6)

Type A (Standard)

The most common HDMI connector for TVs, monitors, and consoles

Pins: 19 pins

  • - 14mm wide
  • - Used on TVs, monitors, game consoles, Blu-ray players
Type C (Mini HDMI)

Smaller version for tablets and some cameras

Pins: 19 pins

  • - 10.42mm wide
  • - Common on DSLR cameras, some tablets
Type D (Micro HDMI)

Smallest HDMI connector for phones and portable devices

Pins: 19 pins

  • - 6.4mm wide
  • - Resembles micro-USB in size
  • - Used on action cameras, some phones
HDMI 1.4 10.2 Gbps 4K @ 30Hz

Added Ethernet channel and 4K support at 30Hz

  • - ARC support
  • - HDMI Ethernet Channel
  • - 3D support
HDMI 2.0 18 Gbps 4K @ 60Hz

Full 4K support at 60Hz with wider color gamut

  • - HDR support
  • - Up to 32 audio channels
  • - Dual video streams
HDMI 2.1 48 Gbps 10K / 8K @ 60Hz / 4K @ 120Hz

Latest standard supporting 8K and high refresh rates

  • - eARC
  • - Variable Refresh Rate (VRR)
  • - Auto Low Latency Mode (ALLM)
  • - Dynamic HDR

Quick ID Tips

1 Distinctive trapezoid shape - wider at the top, narrower at the bottom
2 Flat, thin connector profile compared to VGA or DVI
3 No thumbscrews or locking mechanism (just friction fit)
4 Standard size (Type A) is about 14mm wide
5 Mini and Micro versions are proportionally smaller but same trapezoid shape
6 Usually a black connector and cable

A+ Exam Notes

HDMI carries BOTH audio and video - unlike VGA (video only) or DVI (typically video only)
Know the three physical connector sizes: Standard (Type A), Mini (Type C), Micro (Type D)
HDMI 2.1 is required for 4K at 120Hz and 8K content
HDMI uses HDCP for content protection - important for streaming services
ARC/eARC allows audio to flow from the TV back to a soundbar/receiver over the same HDMI cable

At a Glance

Type Display / Audio-Video
Variants 6
Key Features 8
Exam Tips 5