PCI mezzanine card
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A PCI mezzanine card or PMC is a printed circuit board manufactured to the IEEE P1386.1 standard. This standard combines the electrical characteristics of the PCI bus with the mechanical dimensions of the Common Mezzanine Card or CMC format (IEEE 1386 standard).
The PMC standard defines which connector pins are used for which PCI signals; in addition it defines 64 of the connector pins for use I/O signals.
It enables manufacturers to offer products that are compatible with the well-established PCI bus, but in a smaller and more robust package than standard PCI plug-in cards. The word mezzanine, meaning a platform inserted between two floors of a building, describes the way in which a PMC card fits between two adjacent host cards in a standard card rack, attached to one of the cards by connectors and mounting pillars. A single PMC measures 74 mm x 149 mm. The standard also defines a double-sized card, but this is rarely used.
Carrier cards that accept PMCs are usually made in the Eurocard format, which includes single, double and triple-height VME cards and compact PCI (cPCI) cards.
For the PMC standard, various I/O cards are available: Serial communication controllers, SCSI controllers, Graphics controllers and Firewire controllers.
[edit] Variants
Additional standards exist that define variants of the standard PMC. For example,
- PPMC (processor PMC) defined by the VITA 32 standard
- CCPMC (conduction-cooled PMC) defined by the VITA 20 standard
