Sony America has filed a patent for a Control Docking Unit which would "provide alternate control operation of the portable processing unit (PSP), according to the patent's abstract.
The abstract also mentions that "the controls from the docking unit can be coupled to the portable processing unit using an electrical, mechanical, or electromechanical interface. The electrical interface can be a wired or wireless communication link".
In plain English, Sony patented a hardware interface (unit) that would connect PSP to a Playstation controller. The connection might be wired or wireless, so both PS2 and Sixaxis controller might end up being supported.
Sony did not reveal its intentions for the new interface yet, but several speculations arose. The new configuration might be used to enable some PSP games to benefit from dual-analogue control. It can It can also be used to play Playstation 3 games away from the TV (why would anybody do that?) or the attached PSP might act as an additional display for PS3 games, showing a game's map or a car's rear view.
