So far there are four DC fast charging specs and related connectors, CHAdeMO, Chinese GB, SAE 1772 Combo1 and IEC Combo2. Am I correct? Are there any duplicate or missing connectors here? I didn't buy the IEC specs so cannot tell the whole picture. Each one has different connector layout and communication protocols. If you can design a digital interface inside the charging station, and use different connectors/adaptors on the outside of the charging station, technically you may design a global compatible charging station, is it true? am I missing anything?