VGA connectors pinouts 2/2

Categories:  Electronic
Labels:  pinout, connector

DDC2 (DDC2B) allows bidirectional communication: monitor can tell its parameters and the computer can adjust monitor settings. The bidirectional data bus is a synchronous data bus similar to Access Bus and is based on I2C technology. The signals in the data bus are standard I2C signals. The computer provides 15 kohm pull-up for the SDA and SCLK lines. Monitor must provide 47 kohm pull-up on SCLK line. DDC2B bus is unidirectional and allows only one bus master - the graphics adapter. The monitor acts as a slave device at the 7-bit I²C address 50h, and provides 128-256 bytes of read-only EDID. Because this access is always a read, the first I²C octet will always be A1h.

E-DDC  (Enhanced Display Data Channel) is the most recent revision of the DDC standard. Version 1 was introduced in 1999 and featured up to 32 Kbytes of display information storage for use by the Enhanced EDID (E-EDID) standard. E-DDC Version 1.2, approved in 2007, introduced support for DisplayPort and DisplayID standards

VGA pinout : monitor ID detection pin assignments

This monitor type detection is becoming more and more obsolete nowadays. New VGA plug-and-play monitors communicate with the computer according to VESA DDC standard.

The older VGA pinout with monitor ID is:

Pin Name Dir Description
1 RED -->
Red Video (75 ohm, 0.7 V p-p)
2 GREEN --> Green Video (75 ohm, 0.7 V p-p)
3 BLUE --> Blue Video (75 ohm, 0.7 V p-p)
4 ID2 <-- Monitor ID Bit 2
5 GND --- Ground
6 RGND --- Red Ground
7 GGND --- Green Ground
8 BGND --- Blue Ground
9 KEY - Key (No pin)
10 SGND --- Sync Ground
11 ID0 <-- Monitor ID Bit 0
12 ID1 <-- Monitor ID Bit 1
13 HSYNC or CSYNC --> Horizontal Sync (or Composite Sync)
14 VSYNC --> Vertical Sync
15 ID3 <-- Monitor ID Bit 3
ID pins set-up

4 11 12

n/c n/c n/c no monitor
n/c n/c GND Mono monitor which does not support 1024x768
n/c GND n/c Color monitor which does not support 1024x768
GND GND n/c Color monitor which supports 1024x768

GND means connected to ground
n/c means that the pin is not connected anywhere

15 pin highdensity D-SUB female connector layout
15 pin highdensity D-SUB female connector
at the videocard

15 pin highdensity D-SUB male connector layout
15 pin highdensity D-SUB male connector
at the monitor cable

Source(s) of this and additional information: VGA pinout at the Hardware Book, Tomi Engdahl,