http://www.asus.com.tw/inside/Techref/mediabus.html

The MediaBus connector is a 32-bit PCI bus connector with a 72-pin connector. The longer section of the bus keeps the same PCI pin assignment, which is fully compatible with all PCI add on cards. The shorter section contains the ISA bus signals plus some supplemental signals to support other features such as plug and play. The shorter section is a separate connector which is located in line with the 32-bit PCI bus connector.