Some of the user manuals are telling you need the "Car Dock Mode" application. Only the very first "Car Dock for iPhone" version needed it, all the later coming (round shaped) Car Dock types worked without the application. So you only needed to connect them through Bluetooth (like in the case of the square shaped Car Dock 2).
The SPD1 accapted smartphones between 50-65 mm width. The SPD2 could hold smartphones between 52-74 mm size. The SPH2/IPH2 can do the same between 50-70 mm.
You can download the user manuals from here: