A number of different options are available to expand the board through the PC/104-Plus stackable connectors, a mini PCIe socket, and an SPI/SPX expansion connector. The PC/104-Plus allows stackable system expansion that includes many available PCI and ISA based modules. This allows I/O expansion beyond the native BayCat I/O.  Ethernet, USB, and Serial Ports are a few examples of common stackable expansion modules. The on-board mini PCIe card socket accepts a variety of plug-in modules such as Wi-Fi modems, analog to digital converters, GPS receivers, additional Ethernet ports, flash data storage and other small sized plug-in cards for added flexibility. The SPI/SPX expansion connector allows low-cost analog and digital SPI interconnect expansion modules to be easily added to the system. SPX expansion that uses the SPI protocol, provides an easy way to add low-cost, low-speed I/O expansion such as analog inputs or digital I/O.