modern motherboards often do not broadcast post codes to their pci express slots (pcie switches only pass on transactions after having been configured to do so by the bios). on such motherboards, the low pin count (lpc) bus, an isa variant normally used to connect a trusted platform module (tpm), may be the only bus where post messages can still be seen. however lpc connectors are not standardized, with between 9 and 19 pins and both 2.54 mm and 2 mm pin headers commonly used. therefore, an lpc post card may have to auto-detect first the pin assignment used.