There's three types of DVI mate.
DVI-D
DVI-A
DVI-I
Both pieces of hardware must be the save version for them to be connected. DVI-D being digital and DVI-A being analogue. (DVI-I is just the type of cable and basically its a cable which works with ether format.)
I'm not 100% but im fairly sure that the pin differences are because on newer DVI-D connections the extra pins are not needed which were needed on DVI-A.
DVI-D configuration
DVI-A configuration
DVI-I configuration