This format was created for embedded computer systems by a consortium including Motorola and Ampro Computers. EBX systems typically were embedded PowerPC or PowerQUICC based.

The system board is specified as 8.00 by 5.75 inches (203.2 x 146.05 mm). It incorporates a PC/104-Plus connection subset for peripheral expansion. Optional connectors for PCMCIA are allowed.

Source: Wikipedia (http://en.wikipedia.org/wiki/Embedded_Board_eXpandable)