DVI Pin Mapping for DDC Data and Clock

This article provides a direct reference for the Display Data Channel (DDC) pinout on standard Digital Visual Interface (DVI) connectors. DDC relies on the \(I^2C\) bus protocol to allow the host graphics system to read Extended Display Identification Data (EDID) directly from the monitor. Below, you will find the exact pin assignments for the DDC data and clock lines, along with the complementary power and ground lines necessary for the interface to function properly across DVI-D and DVI-I ports.

Primary DDC Pin Assignments

On all standard DVI connectors (including Single-Link DVI-D, Dual-Link DVI-D, and DVI-I), the DDC clock and data lines are located in the top row of the main 24-pin digital grid:

• Pin 6 — DDC Clock (SCL): Carries the \(I^2C\) clock signal generated by the host to synchronize data transfers.
• Pin 7 — DDC Data (SDA): Carries the bidirectional serial data line used to transmit EDID and display control commands.

Supporting Pins for DDC Operation

For DDC communication to succeed, the interface requires an electrical reference ground and a low-voltage power supply. These signals reside in the middle row of the digital pin block:

• Pin 14 — +5V Power: Supplies 5-volt standby power from the graphics adapter to the display's EEPROM, allowing the host to read EDID data even when the monitor is powered off or in standby mode.
• Pin 15 — Ground (Return for +5V and DDC): Serves as the dedicated ground return line for both the +5V power rail and the DDC clock/data signals.
• Pin 16 — Hot Plug Detect (HPD): Works in tandem with DDC to notify the host system when an active display has been connected, triggering the system to initiate an EDID query over Pins 6 and 7.

These pin assignments remain identical across all consumer-facing DVI specifications, ensuring backwards compatibility for display identification across digital and integrated analog/digital configurations.