Bringing 90s Gaming Back to Life: How One Developer Used AI to Create a Virtual Null Modem for Quake I Online

Somewhere between dial-up screech and the death of serial ports, multiplayer gaming had a charm that's hard to replicate today. A developer named Pieter Branderhorst recently proved that charm isn't entirely lost—he used AI to solve a puzzle that had stumped the retro gaming community for decades.

What Exactly Was a Null Modem?

If you grew up in the pre-network-card era, you probably remember these strange cables sitting around. A null modem was essentially a direct line between two computers, letting you play head-to-head games without any actual network infrastructure. Connect your PC to your friend's PC, fire up a multiplayer session, and frag away.

No router configuration. No firewall troubleshooting. Just two machines talking directly to each other through a wire.

Those were simpler times.

The Quake I Multiplayer Problem

Quake I hit in 1996 and changed everything about first-person shooters. But here's the thing—its multiplayer wasn't designed for the internet as we know it today. It was built for those direct connections we just talked about.

Getting Quake I running in DOS to work with players across the internet? That required some serious creative engineering. For years, it remained one of those "wouldn't it be cool if" projects that never quite materialized.

Until Branderhorst decided to actually do it.

The AI Acceleration

Here's where the story gets interesting. Branderhorst had been poking at this problem for two years. The traditional path forward meant learning low-level COM port manipulation, understanding DOSBox's serial handling, and figuring out WebSocket communication—all skills that take serious time to develop properly.

Then this week happened.

With AI assistance? About an hour to get a working prototype.

His solution creates a web-based virtual null modem. Here's the basic flow: DOSBox intercepts the COM1 communications from Quake I, sends that data through WebSockets to another browser window, and reconstructs the connection on the receiving end. Suddenly, two players anywhere in the world can connect their vintage DOS machines as if they were linked by that old physical cable.

Why This Should Matter to Developers

Look, nostalgia gaming is fun. But the real story here is what this says about AI-assisted development.

AI has the potential to collapse months of learning into hours of actual implementation.

Branderhorst estimates that understanding null modems, DOSBox serial port handling, and bridging them with WebSockets would have taken months of dedicated research. Instead, AI helped him connect the dots in a fraction of that time.

For developers and startups, this is the part worth paying attention to. The conversation isn't really about whether AI makes you faster anymore. It's about whether you're using these tools to tackle problems that previously seemed completely out of reach.

The Tech Behind It

The stack is surprisingly straightforward:

• DOSBox running Quake I in its native environment
• JavaScript handling COM port interception to capture serial data
• WebSockets moving that data in real-time between browser instances
• A minimal HTML interface connecting everything together

No elaborate backend. No cloud infrastructure to babysit. Just smart problem-solving amplified by AI assistance.

This Is Vibe Coding Made Real

We've talked before about vibe coding—that approach where AI helps developers articulate their intent and handles the implementation details that traditionally required years of experience. Branderhorst's project is vibe coding in its purest form.

He had a clear vision. He understood the problem domain. He used AI to bridge the gap between what he wanted and how to actually build it.

The result: a working prototype in an hour that would've otherwise stayed in the "maybe someday" pile forever.

Want to Try It?

If you've got DOSBox and a copy of Quake I lying around, here's how to get started:

1. Exit to DOS (ALT-F4 or FN-Option-F4 on Mac)
2. Head to your Quake directory
3. Launch Quake and hit ESC
4. Go to Multiplayer → Direct Connect
5. Make sure both players use matching settings

The virtual null modem takes care of the rest, creating an internet bridge that makes your DOS machines think they're physically connected.

The Bigger Picture

Stories like this remind me why I enjoy this industry. The web keeps evolving in surprising directions, and AI keeps lowering the barriers to experimentation.

Whether you're reviving retro gaming experiences, building modern applications, or chasing some weird idea that won't leave you alone—the tools available right now make it easier than ever to go from concept to working prototype.

What's an old technology you've been wanting to bridge to the modern web?

Building something creative with AI? We'd love to hear about it—drop a comment below and share how these new tools are helping you bring your ideas to life.