A number of different options are available to expand the board through the PC/104-Plus stackable connectors, mini PCIe socket, and SPI/SPX expansion connector. The industry-standard PC/104-Plus interface allows stackable system expansion for off-the-shelf expansion modules from numerous vendors. 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, and other small sized plug-in cards for added flexibility. In addition, the Mini PCIe socket includes mSATA capability, providing flexible solid-state drive (SSD) options. The SPI/SPX expansion connector allows low-cost analog and digital SPI-based interconnect expansion modules to be easily added to the system. SPX expansion provides an easy way to add low-speed I/O expansion such as Analog or Digital I/O.