# MetraBus Hardware

To use any MetraBus I/O board, a MetraBus interface board, such as the ISA-MDB64, PCI-MDB64 or a CPCI-MDB64, is required for the Universal Library functions to operate correctly. The interface board and a MetraBus cable provide the interface between the PC bus (ISA-, PC104-, PCI-, or CPCI) and the MetraBus I/O Boards.

The MetraBus system is includes at least one controller board that communicates with real-world interface boards via a data bus (ribbon cable). The implication is that there will always be two or more boards in the system.