Sealevel's Proudest Moments
Behind every Sealevel solution is a team of dedicated people. Discover what makes Susan's work the most rewarding.
June 2026: Sealevel’s 40th Birthday Month
Forty Years Strong, and Forward.
What began in 1986 as a commitment to solving real-world engineering challenges has grown into four decades of reliable industrial I/O, rugged computing, and customer-focused innovation.
Three Principles. Forty Years of Progress.
Performance Proven Over Time.
Reliability isn’t a feature, it’s our foundation. For 40 years, Sealevel solutions have delivered dependable performance in environments where failure isn’t an option. From rugged computing platforms to long-lifecycle industrial I/O, our systems are engineered to perform and endure.
Explore ProductsMore Capability, Less Complexity.
Sealevel simplifies development by consolidating engineering, manufacturing, and support while designing platforms integrating computing and I/O. The result is reduced system complexity, fewer integration challenges, and a more efficient path from concept to deployment.
See Our SolutionsConnecting What Matters Most.
Connectivity at Sealevel is built on more than technology, it’s built on relationships. For decades, we’ve partnered with customers, engineers, and integrators to connect systems, operations, and people through dependable, purpose-built solutions.
Connect With UsSealevel at 40
A Legacy 40 Years in the Making
From our earliest designs to today’s advanced platforms, every milestone reflects our commitment to reliability, innovation, and the people behind the products.
1986 Sealevel Founded to Create High-Reliability I/O for Critical Communications
In 1984, Tom O’Hanlan designed the first RS-422/485 communication adapter for the IBM PC. From that moment of inspiration, Tom and his wife Susan saw an ever-growing industry-wide need and began work to fulfill it, forming Sealevel Systems, Inc. in 1986.
1987 Sealevel Named South Carolina Manufacturer of the Year
Sealevel earned early recognition for manufacturing excellence in South Carolina.
1994 Sealevel Awarded First Patent for Isochronous Data Communication System
This milestone reflects Sealevel’s long-standing commitment to engineering innovation.
2000 Products Deployed in Space Through NASA Partnership
Sealevel products supported critical applications beyond Earth’s atmosphere.
Learn more about the NASA project2003 Sealevel Achieves ISO-9001:2000 Certification
Certification reinforced Sealevel’s quality management standards and continuous improvement practices.
2004 Sealevel Adds Design and Manufacturing of Embedded Computers
Sealevel expanded beyond I/O into rugged embedded computing for demanding environments.
2005 Industry’s First RoHS-Compliant PCI Serial and Digital I/O Boards
Sealevel introduced RoHS-compliant PCI RS-232/422/485/530 boards and low-profile PCI digital I/O boards.
2006 Sealevel Moves into New 52,000-Square-Foot Facility
The expanded facility supported continued growth in engineering, manufacturing, and customer support.
Tour Sealevel2010 Tom O’Hanlan Awarded Allan J. McDonald Entrepreneurship Award
The award recognized entrepreneurial leadership and contributions to manufacturing and technology.
Read about the award2011 Sealevel Installs State-of-the-Art SMT Line for In-House Manufacturing
Investment in in-house SMT capabilities strengthened Sealevel’s manufacturing control and product quality.
Explore Sealevel Manufacturing2018 Sealevel Achieves ISO 9001:2015 Certification
Sealevel continued its commitment to quality with certification to the updated ISO 9001:2015 standard.
2018 Tom O’Hanlan Honored with Outstanding Manufacturing Lifetime Service Award
The recognition honored decades of service and leadership in manufacturing.
2022 Sealevel Recognized with South Carolina Transformation and Operational Excellence Award
Sealevel was recognized for operational excellence and transformation within South Carolina manufacturing.
2025 Achieves Prestigious AS9100D Certification
AS9100D certification supports Sealevel’s continued growth in aerospace and defense-related markets.
Read more about AS9100D Certification2026 Sealevel Celebrates 40 Year Anniversary
Sealevel celebrates 40 years of reliability, innovation, and customer-focused engineering.
How Sealevel Systems Built a Legacy of Supporting Critical Operations
At Sealevel, the O’Hanlans made quality a priority from the start with an eye on the future. Ever since, that strategy has guided how the business approaches product and team development, customer support, and community relations.
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Forty & Forward: Sealevel Systems Celebrates 40 years strong
As Sealevel commemorates its past and future with a year-long 40th anniversary campaign, “Forty & Forward,” the company will honor the people, products, and partnerships that have defined its first four decades and support its future-ready vision as a trusted partner.
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Built by People
Who Make It Work
Behind every Sealevel solution is a team of engineers, technicians, and support professionals dedicated to getting it right. Their expertise, collaboration, and commitment power our innovation and strengthen the communities and industries we serve.
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Partner with Sealevel
For 40 years, Sealevel has supported engineers and organizations building systems that demand reliability and longevity. We look forward to partnering with you as you design, deploy, and scale what’s next.
