Pictured: The CC1000dm, a CompactPCI ProcessorPMC carrier card from Emerson Network Power

A CompactPCI system is a 3U or 6U Eurocard-based industrial computer, where all boards are connected via a passive PCI backplane. The pin assignments of the connectors are documented in standards, published by the organization PICMG US and PICMG Europe. PICMG stands for PCI Industrial Computers Manufacturers Group. The connectors and the electrical rules allow for eight boards in a PCI segment. Multiple segments are allowed with bridges.

Unlike the original Eurocards, which use connectors with a 0.1-inch pin spacing, CompactPCI cards use metric connectors with a 2-millimetre pin spacing, designed to the IEC 1076 standard. 3U cards have a 220-pin connector called J1, which carries all PCI bus signals. 6U cards have a second 220-pin connector called J2, which is available for user-defined signals.