FCI Basics PC/104 is an embedded computer standard defined by its compact footprint. The specification is based on the 104 signal contacts on the two bus connectors (64 pins on P1, plus 40 pins on P2). PC/104 Plus is a modular, ruggedized version of the PC 2.00mm pitch. Instead of using a backplane, PC/104 modules mate together via stackable ISA, PCI, and PCIe? bus connectors.