What’s An I/O Board?

Our flagship product, the CmRat, is essentially an I/O board that comes barebone—without any storage, RAM, or CPU attached—but it’s also available in more complete configurations with compute modules like the CM3, CM5, CM5 Lite, and NVMe storage. Sometimes, we refer to the CmRat as a “carrier board” because it supports and integrates components such as RAM, CPU, and storage, much like a motherboard in a PC. However, the more accurate description of the CmRat is an I/O board. But what exactly does that mean?

I/O Board Definition

An I/O board (Input/Output board) is a hardware interface that connects a Compute Module (like the Raspberry Pi Compute Module 4 or 4S) to various peripheral devices, enabling the module to interact with external components and systems. The I/O board expands the module’s connectivity by providing ports and connectors for video, networking, power, storage, and other essential functions.

The Best I/O Boards

What are the top I/O boards? Generally, the best ones offer a strong balance of compatibility, ample ports, and reasonable pricing. Let’s explore some of the top options available on the market.

CmRat

The CmRat, goes beyond affordability and versatility with a strong commitment to open-source principles. DTV Electronics has ensured that the CmRat supports a wide range of applications by embracing open-source software for seamless integration with popular platforms and community-driven projects. This means users benefit from software flexibility and updates directly supported by the open-source community, making the CmRat adaptable for applications like Bitcoin nodes, media centers, and home servers.

Additionally, DTV Electronics has taken a transparent approach to hardware by releasing open schematics, empowering users to modify and adapt the board to their specific needs. This transparency fosters innovation and community collaboration, making the CmRat particularly appealing for tech-savvy enthusiasts who want to dive into the technical details or even build custom hardware extensions.

With features like Gigabit Ethernet (with PoE), HDMI, USB Type-C, a MicroSD slot, and NVMe support, the CmRat is designed to meet the needs of diverse users while remaining accessible. This combination of open-source support and hardware transparency positions the CmRat as a powerful, flexible tool for developers and hobbyists alike, adding value and fostering an ecosystem of continuous improvement and community involvement.

Raspberry Pi Compute Module 4 (CM4) IO Board

The RPi CM4 IO Board is an official solution designed specifically for the Compute Module 4, making it an ideal choice for Raspberry Pi enthusiasts. It provides a rich set of I/O options, including dual HDMI, USB 2.0, Gigabit Ethernet, PCIe, and multiple GPIO pins. This board is perfect for those wanting a reliable and well-supported option for building custom applications with the Compute Module 4, including embedded systems, edge devices, and IoT projects.

Radxa CM5 IO Board

Designed for the Radxa CM5, this I/O board features high-speed connectivity options and PCIe support, making it a powerful platform for intensive tasks. With interfaces like Gigabit Ethernet, HDMI, USB, and PCIe x2, it handles demanding applications well, such as network servers, industrial control systems, and edge computing. This board is a great choice for users looking for a high-performance, compute-intensive solution without breaking the bank.

Waveshare CM4 PoE Board

Waveshare’s CM4 PoE Board is a highly capable and compact I/O solution for the Raspberry Pi Compute Module 4, with Power over Ethernet (PoE) as its standout feature. This board includes Gigabit Ethernet, multiple USB ports, HDMI, and a MicroSD slot, supporting applications from smart home devices to compact servers. With its reliability and compact form factor, it’s an ideal choice for users needing a streamlined solution with PoE support.

Seeed Studio reTerminal CM4 IO Board

The Seeed Studio reTerminal I/O Board is a specialized, industrial-grade board designed for the Raspberry Pi CM4. With a focus on edge computing and IoT, it offers support for Gigabit Ethernet, HDMI, USB 3.0, and rich GPIO access. Its durability and functionality make it well-suited for commercial and industrial applications where reliability and long-term support are essential.

Each of these I/O boards offers unique strengths, so selecting the best option comes down to your specific project requirements—whether that’s affordability, feature set, or specialized functionality.

Why Buying An I/O Board Instead Of Just A Raspberry Pi 5?

Opting for an I/O board instead of a Raspberry Pi 5 offers several benefits, especially for users looking to create custom or specialized systems. Here’s why:

1. Modularity and Flexibility: I/O boards designed for compute modules (such as the CmRat) provide greater modularity. You can select the board with specific features, ports, and interfaces tailored to your needs, rather than relying on the fixed design of the Raspberry Pi 5. This makes it possible to create highly customized setups.
2. Compact Form Factor: Many I/O boards are designed to be compact and fit into small spaces, making them ideal for embedded systems, IoT devices, and applications where space is a premium. The Raspberry Pi 5, in contrast, may have a larger footprint due to its pre-integrated components and connected disks.
3. Enhanced Connectivity Options: High-performance I/O boards often feature interfaces not found on the Raspberry Pi 5, such as PCIe, additional USB ports, PoE (Power over Ethernet), or NVMe support for high-speed storage. This makes I/O boards particularly suitable for network servers, industrial automation, and other applications requiring specialized connectivity.
4. Targeted Use Cases: Compute module I/O boards support more industrial and commercial use cases, where a Raspberry Pi 5 might not meet performance or space requirements. This includes applications like smart displays, point-of-sale systems, and custom IoT solutions.
5. Long-Term Reliability and Customization: I/O boards for compute modules often allow for more advanced cooling solutions, making them better suited for long-term, stable use in demanding environments. Additionally, they allow users to change out compute modules for future upgrades, whereas the Raspberry Pi 5’s board design is fixed.

In conclusion, for DIY enthusiasts, developers, or industrial users with specific project requirements, I/O boards offer a level of customization and functionality that the all-in-one Raspberry Pi 5 cannot match.