How can I use more than one X-Arcade™ (4-player) at a time on my PC/Mac?

You can plug in up to 2 X-Arcade™ dual controllers or 4 X-Arcade™ Solo 1-Player controllers on your PC or Mac. You can plug one X-Arcade™ into the PS/2 port, and any others must go into the USB ports using the USB plug. Alternatively, you can connect all of them into USB ports. You will want to reprogram each controller to use different keys. You cannot plug one X-Arcade™ into another.

For 2 Solos, it is easiest to simply make the 2 Solos act as a 2-player X-Arcade™. To do this, you'll simply want to program one of the Solos to be the player 2 controller, leaving the other in Mode1. Program the player 2 Solo to use the same buttons as the 2nd player side of our 2-player controller.

For 2 trackballs the software must support this, see the MAME™ help section for more on this.