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What is PC/104?
Rugged, Compact, Stackable and Modular

PC104 Spread

PC/104 Definition
PC/104 is an embedded computer standard defined by its compact footprint and its stacking bus structure. In essence, PC/104 is a modular, ruggedized version of the PC. Instead of using a backplane, PC/104 modules mate together via stackable ISA, PCI, and PCIe bus connectors. The stackable connectors and asymmetric corner mounting holes create a compact and modular rugged system.

PC/104 leverages large PC hardware and software markets by following mainstream PC bus development. This reduces time-to-market, and minimizes development costs. Completely defined bus pinouts enable interchangeability and interoperability. This means that users and system designers can choose from a wide array of specialized PC/104 modules to tailor a system to fit their project requirements.

PC104 Size
The compact footprint of PC/104, shown here on an SER25330
Octal-Serial Port module with a PCI/104-Express bus structure.

PC104 Stack
PC/104 stack with CPU, Power Supply and Peripheral Modules. The stack is assembled with PC/104 stand-offs creating a singular and extremely rugged unit.

PC/104 Benefits
The PC/104 concept offers many advantages:

  • Stackable: The design and location of the PC/104 connectors (ISA, PCI, and PCIe) allow PC/104 modules to be connected or stacked like building blocks. A PC/104 stack might include a CPU (single board computer), a power supply module, and peripheral modules such as data collection modules, network modules, or storage devices. Modules within a PC/104 stack are joined by stand-offs.

  • Rugged: PC/104 is inherently rugged. A small footprint and corner mounting holes ensure minimum PCB (printed circuit board) flex in high-vibration scenarios. Many modules are manufactured with extended temperature components, allowing operation from -40 to +85°C. Learn more about RTD's quality and process control.

  • Compact: PC/104 modules occupy a small footprint, but offer highly powerful computer processing and data-collection capabilities. Some applications might require one PC/104 single board computer (SBC) and a power supply. Advanced applications can employ an SBC and multiple special-purpose peripheral modules such as GPS receivers, Ethernet switches, video controllers and data collection cards.

  • Interoperable: PC/104 modules are designed to work together. Users can tailor a system for their specific requirements using multiple PC/104 modules from different PC/104 manufacturers.
PC104 Stack

PC/104 Bus Structures
The PC/104 Specifications are based on a standard size, and a combination of PC buses. From the original PC/104 (ISA) to the latest PCIe/104 (PCI Express) the PC/104 market offers a wide range of bus configurations:

PC104 Bus

PC104 Buses
Pictured Above (left to right): ISA, PCI, and PCI Express connectors.


PC/104 Example Stack
The side-view diagram below shows the versatility of the PC/104 bus structure variations. Here, the stack includes a variety of PC/104 modules driven by PCI Express, PCI, and ISA buses. The interoperable PC/104 standard allows users to take advantage of a huge selection of modules from dozens of PC/104 manufacturers.

PCIe104, PCI-104, PC104 Stack

An example of a PC/104 stack incorporating multiple buses.

Modular PC104 Chassis
RTD's IDAN® packaging technology allows users to configure PC/104 stacks in a rugged enclosure while maintaining the board-level modularity of PC/104. This design is exceptionally useful for upgrades, repairs, and reconfiguration based on mission needs.

PC/104 Specifications
The PC/104 specifications are maintained by the PC/104 Consortium. Specifications for each PC/104 bus structure can be found on the PC/104 Consortium website:

RTD is a leader in the PC/104 Consortium, and proud to be one of its founding members.

PC/104 Deployed
PC/104 systems are deployed in countless applications across the globe and in space. Because of its rugged design, PC/104 systems are ideally suited for extreme environments where equipment failure is not an option.

PC104 Applications

PC104 Enclosures

The examples above show two different PC/104 armored enclosure designs. On the left, RTD's HiDAN® offers a rugged, watertight PC/104 stack housing with a wiring harness and military cylindrical connectors. On the right, RTD's HiDANplus® incorporates the same watertight rugged housing, but it also maintains the modular stackability of PC/104. Learn more about RTD's rugged PC/104 enclosure options.