The Standard Density D-Sub is the original D-Sub created some 50 years ago, the Standard Density D-Sub have signal contacts with current rating of 5A. There are 5 sizes with connector mating layouts ranging from 9 positions to 50 positions. This connector is widely used in industrial applications worldwide.
If more positions is needed there is another alternative, The High Density D-Sub, see below.
The High Density D-Sub have the same size as the Standard Density connector but hold more contacts in its insulator. For a Standard Density 9 position connector the High Density holds 15 positions, for a 15 position Standard Density connector, the High Density holds 26 positions, and so on, see Tech Specs for more details. The High Density connector have a drawback in comparison and that is the current rating which is only 3Aas the Standard Density have 5A .