PC/104
Specification: PC/104
Version: 2.6
Latest Release: October 13, 2008
Status: Active
Dimensions: 3.775 x 3.550 in.
Stackable Buses: ISA
This is the original form factor created by the Consortium at the beginning of our history. It may be used for both SBC and I/O boards. It includes only the ISA connector, offering connectivity to I/O boards dating all the way back to the origins of PC/104, many of which are still available today. Depending on the host SBC, up to 10 ISA boards may be used in a single system. The standard board size is 3.55 x 3.775” / 90 x 96mm. Boards can be up stacking, down stacking, or bi-directional stacking.
The original PC/104 standard was oriented around the ISA bus (per IEEE P996), as used in early "personal computers". This format pioneered the concept of stacking expansion.
Unlike the larger PC motherboards, the PC/104 format features:
Compact form-factor. Only 3.6 by 3.8 inches.
Self-stacking bus. Eliminates the cost and bulk of backplanes and card cages for expansion.
Pin-and-socket connectors. Rugged and reliable pin headers replaced the PC’s edge-card connectors.
By virtue of the PC/104 format, companies embedding PC technology in limited space applications were able to benefit from a standardized architecture with a wide range of functions and multi-vendor support.
After the release of the PC/104 specification, and as technological requirements advanced, a need arose for higher performance bus throughput. The Consortium met this challenge by incorporating a PCI bus on the PC/104 form factor, which became known as PC/104-Plus. This architecture provided a link to versatile legacy hardware while meeting newer speed requirements.
PC/104-Plus
Specification: PC/104-Plus
Version: 2.3
Latest Release: October 13, 2008
Status: Active
Dimensions: 3.775 x 3.550 in.
Stackable Buses: ISA and PCI
The PCI-104 specification is a follow-on to the PC/104-Plus spec. PCI-104 is a PCI-only architecture that accommodates the advances of PCI devices in the rugged, PC/104 form factor.
PCI-104
Specification: PCI-104
Version: 1.1
Latest Release: October 13, 2008
Status: Active
Dimensions: 3.775 x 3.550 in.
Stackable Buses: PCI
The Embedded Board eXpandable (EBX) specification defines a compact, open-standard form factor for embedded single-board computers (SBCs). Designed to meet the space, power, and reliability demands of embedded systems, EBX enables OEMs to use off-the-shelf components instead of proprietary solutions. It supports modular expansion through widely adopted standards like PC/104, PCI-104, and PCMCIA, offering flexibility and scalability. EBX boards are small enough for space-constrained environments but powerful enough to support modern operating systems and full system functionality.
EBX™
Specification: EBX
Version: 3.0
Latest Release: June 23, 2008
Status: Active
Dimensions: 8.00 x 5.75 in.
Stackable Buses: ISA and PCI
This specification introduces a mid-sized embedded Single Board Computer (SBC) platform that fills the gap between the compact PC/104 stackable format and the larger EBX form factor. Designed to support higher-performance processors and larger heat sinks, it enables integration of more features onto a single board—reducing the need for multiple expansion modules. The platform supports flexible I/O expansion through standards like PC/104, PCI-104, USB, and Ethernet, and emphasizes generous space for I/O connectors. As an open-architecture and industrial-grade solution, it offers embedded system designers a standardized, space-efficient option for building powerful, scalable systems.
EPIC™
Specification: EPIC
Version: 3.0
Latest Release: June 23, 2008
Status: Active
Dimensions: 8.00 x 5.75 in.
Stackable Buses: ISA and PCI
