The PlayStation 3 is backward-compatible with virtually all PlayStation and PlayStation 2 games, but peripherals are another story. The PlayStation 3 lacks legacy controller ports, so all (non-USB) PlayStation and PS2 alternative controllers such as guitar controllers, dance pads and fighting sticks and pads cannot be connected directly to a PS3.
You can play alternative controller-supported legacy games like Guitar Hero, Dance Dance Revolution and Street Fighter Collection 2 with a standard PlayStation 3 Sixaxis controller, but they are not fun that way, and in the case of Street Fighter Collection 2 and other fighting games, they can be painful.
PlayStation/PS2 controller-to-USB adapters have been around longer than the PlayStation 3, but the lack of "Analog" buttons--the PlayStation/PS2 "Analog" button is the same as the PS3 "PlayStation Home" button--on many alternative controllers prevents them from enabling themselves and assigning controller numbers on a PS3 (and prior to the System Software 1.70 update, most adapters did not work with PlayStation and PlayStation 2 games, only PlayStation 3 games). Additionally, Hori and Sega's PlayStation 3 fighting sticks work only with PlayStation 3 games, not PlayStation and PlayStation 2 games (even after the 1.70 update), making them less than ideal unless all your fighting games are for the PS3.
Enter the PS2 to PS3 Adapter Controller Dongle from Pelican. With a "PlayStation Home" button on the adapter itself, Pelican claims it is "compatible with all PS2 controllers including: DualShock 2 controllers, wireless controllers, guitars, steering wheels, arcade fighting sticks, dance mats and more," and makes specific mention on the front of its packaging that it "works with Guitar Hero 1 & 2." This adapter has the potential to return the fun to alternative controller-supported legacy games on a PlayStation 3.
So, does it return the fun?
The PS2 to PS3 Adapter is better than all other PlayStation/PS2-to-USB adapters, but it is not as compatible as Pelican claims.
Initial tests show that this adapter works with the wired Guitar Hero SG Controller, Street Fighter 15th Anniversary Controller, Ascii Pad FT2 and Cordless Action Controller, all with no apparent input lag--there is a delay between pressing the "Mode" ("Analog") button on a Cordless Action Controller and the menu appearing, but its gameplay buttons perform perfectly. Guitar Hero is fun again and Street Fighter Collection 2 is no longer painful thanks to the PS2 to PS3 Adapter.
The Guitar Hero Wireless Controller and Wireless Anashin 2 do not work with the PS2 to PS3 adapter. So much for "compatible with all PS2 controllers." It is understandable that the Wireless Anashin 2 does not work; it was available only in Japan and discontinued years ago. It is not understandable and not acceptable that the Guitar Hero Wireless Controller does not work. The Guitar Hero games are among the currently most popular for the PlayStation 2, and the official Guitar Hero Wireless Controller is widely available. Pelican has no excuse for not testing it with its adapter. It is difficult to go back to wired controllers after you have used wireless ones.
Also, while the PS2 to PS3 Adapter works perfectly with the original Guitar Hero (provided you use the wired guitar controller), Guitar Hero II support is a hack. The adapter has a switch to toggle between "Normal" and "GH2" modes, but switching this switch is not the only thing you need to do to play Guitar Hero II with this adapter. You have to be in the "menu" sub-mode (press "Start" and the green fret button on the guitar controller) to navigate menus, switch to "Righty" or "Lefty" sub-mode (press "Start" and the red or yellow fret button respectively) to perform songs, switch back to "Menu" when a song is finished to navigate the new menu, switch back to "Lefty" or "Righty" to perform the next song and so on. Hammer-ons and Pull-offs are not supported, and Star Power can be activated only by pressing the "Select" button; tilting the guitar controller upward does nothing. Even if you could live with the limitations and constant switching of sub-modes, it would not be worth it; the PS2 to PS3 Adapter is laggy when used with a wired guitar controller for Guitar Hero II.
Finally, the Pelican PS2 to PS3 Adapter does not support vibration. If you want the rumble back in your PlayStation and PlayStation 2 games, look elsewhere.
Still, Pelican's PS2 to PS3 Adapter Controller Dongle works with enough legacy peripherals to make it attractive. Just don't buy it expecting to once again play Guitar Hero II with your official Guitar Hero Wireless controller.