Nearly all modern PC graphics cards use the same 15 pin conenctor that the original IBM VGA card used. The connector is not very suitable for high resolution graphics because it does not have a well defined impedance characteristics like BNC connectors. 15 pin VGA connector is still commonly used because it is so popular that it is hard to sell product without it.
Pin 1,2,3 are analogue 0.7V p-p positive signals to 75 ohm load. All other signals are TTL level signals.
