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. In 1986, they formed Sealevel Systems, Inc. committed to providing reliable, well-designed communication adapters for the IBM PC and compatibles.

Why the name Sealevel?

Tom wanted a name that didn’t sound like a computer company. After listening to music (his other passion), the word Sealevel came to Tom’s mind. In a serendipitous coincidence, the jazz/blues/rock band that had once backed The Allman Brothers Band, released their self-titled debut album in 1977. Their name? Sea Level. In 1986 Sealevel the company was born. Today, Sea Level bandleader and acclaimed keyboardist, Chuck Leavell, is the celebrity spokesperson for Sealevel Systems, Inc. and Tom’s trusted friend.

More than 35 years later, Sealevel continues to provide innovative, reliable hardware and software products to enable computer connectivity and control. Today, we manufacture more than 300 standard I/O products with ISO 9001: 2000 registration and a standard lifetime warranty.

Because the needs of our customers are ever-evolving, we’re constantly developing new products that leverage emerging technology. We’re obsessive and passionate about what we do – from customer service to intuitive design to tech support. We do our jobs to the best of our ability because we understand the products we create help our clients make the world stronger, safer, and better.


Find out what drives us and make us. Take a closer look at Sealevel.

Core Leadership

Meet the managers that keep our team shipshape.