System on Modules (SOM): The Complete Guide to Embedded Computing
Written by: Stephen Athokpam, Embedded Computing & Industrial Systems Specialist, Portwell India
Published On: 08 September 2026
Table of Contents
A System on Module (SOM) also called a Computer on Module (COM) is a compact, production-ready circuit board that integrates a processor, memory, storage, power management, and core interfaces into one module. It plugs into a carrier board that adds the application-specific I/O, letting product teams build embedded systems faster without designing the entire computing architecture from scratch.
Portwell designs and manufactures System on Modules including COM Express and Qseven form factors along with PICMG SBCs and industrial motherboards for OEMs building industrial, automation, and edge-computing products.
What Is a System on Module (SOM)?
A System on Module (SOM) sometimes called a Computer on Module (COM), as the two terms are used interchangeably in the industry is a compact embedded computing board that integrates the processor, memory, storage, and power circuitry needed to run an operating system and application software.
A SOM may include:
- Processor or System on Chip (SOC)
- RAM
- Flash or eMMC storage
- Power management circuitry (PMIC)
- Graphics or AI acceleration (GPU/NPU)
- Ethernet and USB interfaces
- Wireless connectivity
- Security components
- High-speed communication interfaces
Instead of designing these components individually onto a custom PCB, developers integrate a pre-engineered SoM into a carrier board built around their application separating the computing platform from the application-specific hardware.
Quick Fact Box
- SOM: Computer on Module (COM) same concept but different name
- A SOM is not a Single Board Computer (SBC) as it needs a carrier board
- A SOM is not a System on Chip (SOC) instead one chip and a full board built around one
How Does a System on Module Work?
A SOM-based embedded system has three major parts:
System on Module -> Carrier Board -> End Product.
The SoM is responsible for computing, while the carrier board distributes the power and the signals to displays, sensors, and industrial I/O of the end product.
For example, a machine vision inspection system that requires Ethernet, CAN, USB, and a display can use Portwell SoM (for computation) with custom-designed Carrier Board that handles those interfaces, avoiding a complete custom chip-down design and shortening the development time by months.
As a result, this design allows the engineers to focus on the application-oriented features instead of developing the whole embedded computer from scratch.
What Components Are Included in a System on Module?
| Component | Function | Common Options |
|---|---|---|
| Processor / SOC | Core compute | ARM, x86, RISC-V based SOCs |
| RAM | Runs OS + apps | LPDDR4 / LPDDR4X, DDR4 |
| Storage | OS + application data | eMMC, NAND, NOR flash |
| Power Management (PMIC) | Regulates / distributes power | PMIC-based circuits |
| Connectivity | I/O to carrier board | Ethernet, USB, PCIe, CAN/CAN-FD, MIPI |
| Acceleration | AI / vision workloads | GPU, NPU, DSP, FPGA |
| Security | Data / boot protection | Secure boot, hardware security elements, secure storage |
SOM vs SOC vs SBC — What's the Difference?
A SOM is a compute module that requires a carrier board; a SoC is a single chip requiring full custom PCB design; an SBC is a complete, ready-to-use computer needing no carrier board. Most embedded product teams get the best balance of speed and customization from a SoM.
| Feature | System on Module | System on Chip | Single Board Computer |
|---|---|---|---|
| Definition | Complete computing module | Computing architecture integrated into a chip | Complete computer on a board |
| Processor | Included | Included | Included |
| Memory | Often integrated | May be integrated or external | Included |
| Carrier Board | Usually required | Custom PCB required | Usually not required |
| Customization | High | Very High | Moderate |
| Hardware Development | Reduced | Significant | Low |
| Time to Market | Faster | Longer | Fast |
| Best Suited For | Embedded products | Highly customized hardware | Prototyping and complete systems |
SOM vs Chip-Down Design: Which Should You Choose?
Choose a SOM for faster time to market, lower engineering cost, and lower hardware-expertise requirements.
Choose chip-down design only for highly specialized, high-volume products where maximum hardware control justifies the added cost and time.
| Factor | SoM-Based Design | Chip-Down Design |
|---|---|---|
| Development Effort | Lower | Higher |
| Time to Market | Faster | Longer |
| Initial Engineering Cost | Generally lower | Generally higher |
| Hardware Customization | High | Maximum |
| Hardware Expertise Required | Lower | Higher |
| Design Flexibility | High | Very high |
| Prototype Development | Faster | Slower |
| Product Scalability | High | Depends on design |
| Best Suited For | Many embedded products | Highly specialized / high-volume products |
SoM Form Factors: Edge Connector vs. Mezzanine vs. Solder-Down
SoMs come in three main mechanical form factors — edge connector, mezzanine connector, and solder-down (SMD) each suited to different design and volume needs.
| Form Factor | Characteristics | Best For |
|---|---|---|
| Edge Connector | Widely used industry standard (e.g., COM Express, Qseven); larger footprint due to connector | Standard industrial designs, easy field upgrades |
| Mezzanine Connector | More efficient use of board space than edge connectors | Space-constrained designs needing swappability |
| Solder-Down (SMD) | Mechanically robust, low profile, suited to automated assembly | High-volume production, rugged/vibration-heavy environments |
Portwell’s COM Express and Qseven modules use industry-standard edge-connector form factors, giving OEMs a proven, pin-compatible upgrade path across processor generations.
Real-World Applications of System on Modules
SoMs provide processor boards for a variety of industries requiring computing solutions that are compact, reliable, and can be deployed in the field.
- Industrial Automation and Robotics SOMs are enabling PLCs, robot controllers, and other factory automation systems requiring real-time processing and rugged components the main focus in the Portwell industrial PC line and embedded box PCs.
- Machine Vision and Quality Inspection SOMs with a GPU/NPU on board can process images directly on the device, which is key for defect detection, inventory inspection, and signature analysis on the manufacturing lines where any delay would not be acceptable.
- IoT Gateways and Edge Computing SOMs powered with different wireless technologies are collecting the sensor data and processing it locally before transferring to the cloud, which allows reducing costs and latency due to lower usage of bandwidth.
- Medical and Diagnostic Devices SOMs are compact and low-power solutions for any patient monitoring devices and diagnostic equipment where reliability and availability of parts for extended time period are essential.
- Transport and Kiosks Industrial panel PCs and displays built around SOM/SBC technologies drive digital signage, ticket vending machines, transport systems, and other devices that need uninterrupted performance in various environments.
Talk to Portwell about your application
Our team can recommend the right processor, form factor, and carrier-board approach for your specific I/O, environmental, and volume requirements.
Enquire NowBenefits of Using a System on Module
- Faster time to market: Core compute is pre-integrated and pre-validated Â
- Reduced hardware complexity: Power, memory, and thermal design are handled by the module vendor
- Lower Development Risk: Build on a proven, tested platform instead of a from-scratch design
- Flexible Product Design: One SOM, multiple carrier-board variants for different product tiers
- Easier scaling: Build entire product families off a single compute platform
- Simplified Lifecycle Management: Upgrade or swap the SoM without redesigning the whole product
- Vendor Software Support:BSPs, Linux kernel, device trees, and drivers cut software bring-up time drivers.
How to Choose the Right SOM: A Buyer's Checklist
- Processor/SoC performance : Match compute and AI-acceleration needs to your workload
- Memory & storage capacity: Size RAM/storage to your OS, app count, and data-processing needs
- Required I/O interfaces: Ethernet, USB, PCIe, CAN/CAN-FD, MIPI, display outputs
- Form factor & connector type: Edge connector (COM Express, Qseven), mezzanine, or solder-down
- Thermal and environmental requirements: Industrial temperature range, vibration, humidity
- Available PCB space and mechanical constraints
- Production volume and cost targets
- Security requirements: Secure boot, hardware security elements, secure storage
- Vendor longevity & software support : BSP quality, documentation, long-term part availability
- Future upgrade path: Â pin-compatible module families reduce redesign cost later
Not sure which spec matters most for your project?
We'll walk through your I/O, environmental, and volume requirements and recommend a module
Talk to a Portwell engineerFrequently Asked Questions
A SOM is a compact circuit board that integrates a processor, memory, storage, and power management into one module, designed to plug into a carrier board for use in an embedded product.
None functionally. System on Module (SOM) and Computer on Module (COM) refer to the same type of product and are used interchangeably across the industry.
The SOM provides the processor, memory, storage, and power management. The carrier board supplies the application-specific interfaces displays, sensors, industrial I/O that connect to the SOM.
No. An SBC is a complete, ready-to-deploy computer that typically doesn't need a carrier board, while a SOM must be paired with a carrier board to function in a product.
The three main form factors are edge connector (e.g., COM Express, Qseven), mezzanine connector, and solder-down (SMD). Each suits different space, volume, and ruggedness requirements.
A SOM reduces engineering effort, cost, and risk by using a pre-validated compute platform, letting teams focus on application-specific carrier-board design instead of processor-level hardware engineering.
Industrial automation, robotics, machine vision, medical devices, IOT gateways, transportation, and kiosks/digital signage are among the most common applications.
Many SOMs include GPU, NPU, DSP, or FPGA acceleration to support AI inference and image processing locally, without relying on cloud processing.
Evaluate processor/SOC performance, memory and storage needs, required interfaces, form factor, thermal constraints, security features, and the vendor's software/BSP support and long-term availability.
Looking for a System on Module for your next embedded product?
Portwell designs COM Express, Qseven, and PICMG SBC platforms for industrial and edge-computing applications
backed by long-term availability and direct engineering support.
Stephen Athokpam
Stephen Athokpam is an Embedded Computing Systems Specialist at Portwell, covering COM Express modules, industrial motherboards, and edge AI systems for OEMs and system integrators.
