What is the difference between a UniversalPCI board and a PCI board?
A. The original PCI standard required that plug-in boards use 5V signaling provided by the PCs motherboard. As the PCI standard evolved, the option was added for a 3.3V signaling. Now, with the latest PCI 2.3 release, all PCI plug-in boards are required to support 3.3V signaling. In order to make sure that a plug-in board receives the correct voltage (as getting the wrong voltage would cause the PC to be badly damaged) a different set of keys was designed for each voltage type. The key is the arrangement of gold fingers at the bottom of the board. Click to see a picture of PCI keying. When a board is inserted into a PCI slot, those goldfingers fit into the appropriate socket. Motherboards using 5V signaling can only accept PCI cards keyed for 5V. Motherboards using 3.3V signaling can only accept PCI cards keyed for 3.3V. Both PC manufacturers and PCI board developers realize that users would optimally like a combination of both options. So, some motherboards provide universal connector
