VGA analogue display connector

Nearly all PC graphics cards use the same 15 pin connector that the original IBM VGA card used.
The only thing that has changed is the monitor detection / communication.

VGA connector picture

Pin numbering of female connector

Pinout (in / out as seen from PC Graphics card)

  
pin     IBM vga             Vesa DDC1           Vesa DDC2  

1       Red out *           Red out *           Red out *         
2       Green out *         Green out *         Green out *
3       Blue out *          Blue out *          Blue out *
4       Monitor ID 2 in     Monitor ID 2 in     Monitor ID 2 in
5       Ground              Ground              Ground
6       Red return          Red return          Red return
7       Green return        Green return        Green return
8       Blue return         Blue return         Blue return
9       no pin              optional 5V out     optional 5V out
10      Sync return         Sync return         Sync return
11      Monitor ID 0 in     Monitor ID 0 in     Monitor ID 0 in
12      Monitor ID 1 in     Serial data in      Bidirectional I2C data (SDA)
13      Horizonal Sync out  Horizonal Sync out  Horizonal Sync out
14      Vertical Sync out   Vertical Sync out   Vertical Sync out
15      (Monitor ID 3)      Monitor ID 3 in     Data clock (SLC)
Signals marked with * are analogue 0.7V p-p positive signals into 75 ohm load. All other signals are TTL level signals.

Original IBM Monitor ID detection pin assignments

4    11   12
ID2  ID0  ID1

NC   NC   NC   no monitor
NC   NC   GND  Mono monitor which does not support 1024x768
NC   GND  NC   Color monitor which does not support 1024x768
GND  GND  NC   Color monitor which supports 1024x768

GND means connected to ground, NC means that the pin should not be connected anywhere.
This monitor type detection is becoming more and more obsolete nowadays, because more intelligence is integrated to the monitor. New plug-and-play monitors communicate with the computer according to VESA DDC standard.

Pinout diagram for a modern DDC2 VGA connector :

(Pin numbers are the same for male or female)          female_outside: 
                                                              6
 1 Red         6 Red   Return    11 (ID0 GND)              1  .  11
 2 Green       7 Green Return    12 Serial Data             . . .
 3 Blue        8 Blue  Return    13 Horizontal Sync         . . .
 4 (ID2 GND)   9 NC (5V)         14 Vertical Sync           . . .
 5 Ground     10 Sync Ground     15 Data Clock              . . .
                                                           5.10 .15

credits: Tomi Engdahl, http://www.hut.fi
ePanorama.net - Circuits