Trans Travel released this useful concept of a universal docking collar. It allows any two ships thus equipped to dock and allow their crews to access each vessel without the need for space suits. The collar portion extends past any extensions of the starship to connect with the other vessel's own collar, and the two interlinked air locks are then pressurized to allow easy access between ships. The telescopic portion of a UAD may also connect to a non-UAD craft presuming the hull is smooth and flat around the hatch, otherwise the usual spacewalking rules apply. Cost is 10,000Cr with a MHS=3.

(source - House Rules WIKI)