What Is Pin 14 on a DVI Connector?

On a standard DVI (Digital Visual Interface) connector, pin 14 is dedicated to providing +5V DC low-current power from the host computer to the display device. This article details the operational role of pin 14, explaining how it powers the monitor's identification circuitry, facilitates Display Data Channel (DDC) communication, and assists with plug-and-play hardware detection.

The Role of Pin 14: +5V Power

Pin 14 serves as an auxiliary power supply carrying direct current at +5 volts (typically capable of supplying at least 55 mA, up to a standard maximum of around 500 mA). Unlike the pins responsible for transmitting high-speed digital video signals (TMDS channels), pin 14 does not carry image data. Instead, it provides the electrical current necessary to power specific low-voltage components inside the display interface.

Powering EDID and DDC

The main objective of pin 14 is to supply electrical power to the monitor’s onboard EEPROM chip, which stores Extended Display Identification Data (EDID).

When a computer boots up or a cable is connected, the graphics card reads this EDID memory block via the I²C-based Display Data Channel (DDC), using pin 6 (DDC Clock), pin 7 (DDC Data), and pin 15 (Ground return for +5V). Because pin 14 supplies power to the EEPROM, the host computer can query the monitor's supported resolutions, refresh rates, manufacturer details, and color profiles even if the monitor is in standby mode or completely unplugged from wall power.

Facilitating Hot Plug Detection and Adapters

Pin 14 also plays an indirect role in display detection:

  • Hot Plug Detection (HPD): The +5V line is often routed through the monitor circuitry to assert a high signal on pin 16 (Hot Plug Detect). When this signal is received back at the graphics card, the system recognizes that a display has been connected.
  • Active Converters: Active adapters that convert DVI to VGA, HDMI, or DisplayPort rely on pin 14 to draw the operational power required to run their internal digital-to-analog or protocol conversion chips without needing an external wall adapter.

Symptoms of Pin 14 Failure

If pin 14 is bent, broken, or suffers a blown inline fuse on the graphics card:

  • The operating system will fail to identify the monitor's model and native resolution, often falling back to a generic, low-resolution "Standard VGA" mode (e.g., 640x480 or 1024x768).
  • Plug-and-play detection will fail when connecting the cable while the PC is running.
  • Active DVI-to-VGA or DVI-to-HDMI converters will not power on or output a signal.