This made me curious and I found this page on wikipedia: http://en.wikipedia.org/wiki/Spacecraft_Docking_and_Berthing...
Totally fascinating subject. It wasn't clear to me if Dragon 2 is going to use the APAS-95 connector (what the Shuttle used), or the newer NDS connector.
It also made me think.. was there some kind of adapter used for Apollo missions after Apollo 13 for the CO2 scrubbers? Or was the hack the "official way" of getting around problem?