TMDS Shield Pin Locations in a DVI Connector

In a Digital Visual Interface (DVI) connector, Transition-Minimized Differential Signaling (TMDS) shield pins are positioned directly adjacent to their corresponding differential data and clock pairs. This article provides a clear breakdown of the physical pinout configuration, detailing exactly where each shield pin sits within the standard 24-pin connector grid to isolate signals, maintain characteristic impedance, and minimize cross-talk between high-speed video channels.

The 24-Pin Digital Layout

A digital DVI connector (DVI-D or the digital portion of DVI-I) organizes its 24 pins into a grid of three horizontal rows, each containing eight pins. The high-speed TMDS lines—carrying data and clock signals—are balanced differential pairs running alongside dedicated ground shield pins.

Row-by-Row Shield Pin Positioning

The shield pins are interleaved within each row, typically separating the primary single-link data pairs from the secondary dual-link data pairs:

  • Row 1 (Pins 1–8):
    • Pins 1 & 2: TMDS Data 2− and Data 2+
    • Pin 3: TMDS Data 2/4 Shield
    • Pins 4 & 5: TMDS Data 4− and Data 4+
    • Location: Pin 3 is placed directly between the Data 2 pair and the Data 4 pair, acting as an electrical barrier between Link 1 and Link 2 data lines.
  • Row 2 (Pins 9–16):
    • Pins 9 & 10: TMDS Data 1− and Data 1+
    • Pin 11: TMDS Data 1/3 Shield
    • Pins 12 & 13: TMDS Data 3− and Data 3+
    • Location: Pin 11 is positioned immediately between the Data 1 pair and the Data 3 pair, isolating the green channel lines of both links.
  • Row 3 (Pins 17–24):
    • Pins 17 & 18: TMDS Data 0− and Data 0+
    • Pin 19: TMDS Data 0/5 Shield
    • Pins 20 & 21: TMDS Data 5− and Data 5+
    • Pin 22: TMDS Clock Shield
    • Pins 23 & 24: TMDS Clock+ and Clock−
    • Location: Row 3 contains two distinct shield pins. Pin 19 sits between the Data 0 pair and the Data 5 pair. Pin 22 sits directly next to the differential TMDS Clock pair (Pins 23 and 24), isolating the continuous clock reference from the adjacent high-frequency data lines.

Functional Purpose of Shield Placement

Placing shield pins directly adjacent to and between the differential pairs creates a coplanar ground reference. In twisted-pair cabling, the shield wire wraps around or runs parallel to each respective differential pair before terminating at these specific pins. This physical proximity ensures that electromagnetic interference (EMI) is shunted to ground, external noise is rejected, and intra-cable skew and crosstalk between the high-speed channels are significantly suppressed.