Questions related to berthing a craft or module to the ISS. A distinction is made between berthing and docking.
In the context of the ISS there are two methods for visiting craft to connect to the station. Berthing is used by the Dragon, Cygnus, and HTV cargo space craft. They approach the station, hold their location and the CanadArm2 picks up the vehicle and berths it to a CBM (Common Berthing Port) which has a wider door than a PMA (Pressurized Mating Adapter).
The manned vehicles for the US Segment planned will all dock to a PMA, without requiring intervention from the station in the same way.