DVI Port DDC Serial Clock Pin Designation

This article provides an overview of the pin configuration for Digital Visual Interface (DVI) connectors, specifically identifying the exact pin assignment for the Display Data Channel (DDC) serial clock. It explains the functional role of this pin in monitor detection, EDID data transfer, and how it fits into the broader DVI pinout architecture across various connector formats.

On a standard DVI connector—including DVI-D (digital only) and DVI-I (integrated digital and analog), in both single-link and dual-link formats—the DDC serial clock line is designated as Pin 6.

Function of the DDC Serial Clock (SCL)

Pin 6 carries the I²C-compatible clock signal (SCL) utilized by the Display Data Channel protocol. The graphics processing unit (GPU) uses this dedicated clock line to synchronize serial communication with the display device. Through this channel, the host system reads the monitor's Extended Display Identification Data (EDID), which contains vital operational parameters such as supported resolutions, refresh rates, native aspect ratios, and color profiles.

The DDC serial clock operates alongside three other vital low-speed communication pins located in the central group of the primary 24-pin matrix:

  • Pin 6 (DDC Clock / SCL): Synchronizes data transmission across the interface.
  • Pin 7 (DDC Data / SDA): Carries the bidirectional data stream between the host and display.
  • Pin 14 (+5V Power): Supplies low-voltage standby power to the display's EEPROM so the computer can read EDID data even when the monitor is turned off.
  • Pin 15 (Ground): Acts as the dedicated return path and ground reference for Pin 6, Pin 7, and Pin 14.

Because the DDC channel uses a standard bus architecture independent of high-speed video data, Pin 6 retains the identical physical location and electrical function across all variations of full-size DVI ports.