Setting up Duet Over Thunderbolt significantly improves performance by offering speeds of 10Gb/s+ and near-zero lag (<1ms). It also keeps high-bandwidth 4K video off your local Wi-Fi network.

Hardware Requirements

• Ports: Both devices must have Thunderbolt 3 or higher. Look for the lightning icon (⚡) next to the USB-C port.
• Cables: You must use a dedicated Thunderbolt cable (standard USB-C charging cables will not work).
• Operating System: Windows users must be on Windows 10 (version 1709) or later.

Here's a quick visual guide to identify Thunderbolt cables and ports:

Configuring Mac-to-Mac

1. Close Duet Display on both Macs.
2. Connect the Thunderbolt cable to both Macs.
3. Go to System Settings > Network.
4. Look for Thunderbolt Bridge:
   
   1. Yellow Dot: macOS has assigned a "Self-Assigned IP." You are ready!
   2. Red Dot: The connection isn't detected. Try a different port or cable.
5. Open Duet on both Macs and start a connection.

Configuring Mac-to-Windows

1. Close Duet Display on both computers.
2. On Mac (Internet Sharing): Go to System Settings > General > Sharing.
   
   1. Enable Internet Sharing from your active internet (e.g., Wi-Fi) to Thunderbolt Bridge. (Skip this if using Windows 11).
3. On Mac (IP Setup):
   
   1. Go to Network > Thunderbolt Bridge > Details > TCP/IP.
   2. Set Configure IPv4 to Manually.
   3. IP Address: 10.10.10.1 | Subnet Mask: 255.255.255.0.
4. On Windows (IP Setup):
   
   1. Go to Control Panel > Network and Sharing Center > Change adapter settings.
   2. Right-click the Thunderbolt connection > Properties > IPv4.
   3. Set IP Address: 10.10.10.2 | Subnet Mask: 255.255.255.0.
5. Open Duet on both devices and start a connection.

Configuring Windows-to-Windows

1. On Both PCs: Go to Advanced sharing options and turn on Network discovery and File/Printer sharing for Private networks.
2. On PC 1 (The Host/Sender): Go to Network Connections, right-click your active Internet source, and select Properties.
   
   1. Under the Sharing tab, allow other users to connect through this computer and select the Thunderbolt network from the dropdown.
3. On PC 2 (The Client/Receiver): In Network Connections, right-click the Thunderbolt adapter > Properties > IPv4.
   
   1. Ensure it is set to Obtain an IP address automatically.
4. Open Duet on both devices and start a connection.

How to Verify it's Working

The most reliable way to confirm your devices are actually using the high-speed Thunderbolt bridge (and not your Wi-Fi) is a quick "Ping" test.

1. Open your command line: Use Terminal (Mac) or Command Prompt (Windows).
2. Run the test: Type ping followed by the IP address of the other computer.
   
   1. Example: ping 10.10.10.1‍
3. Analyze the results:
   
   1. 0% Packet Loss: Success! Your devices are communicating directly over the cable.
   2. "Request Timed Out": The devices aren't seeing each other. Double-check that your manual IP addresses match the same range (e.g., 10.10.10.1 and 10.10.10.2).
   3. High Latency: If you see "Time" values higher than 1ms-2ms, you might still be routing through your Wi-Fi network. Try disabling Wi-Fi temporarily to force the Thunderbolt path.

Troubleshooting Tips

• If Duet Display is connecting over Wi-Fi instead of Thunderbolt after following these steps, quit and reopen the Duet app on both devices and then try again.
• When establishing the connection for the first time, your Mac or Windows device may need to reboot to properly initialize the network adapter and load new drivers.
• If the connection isn't recognized at all, visit your manufacturer’s website to update your Thunderbolt drivers or firmware.
• If issues persist, try a different Thunderbolt cable and double-check that you are using the specific Thunderbolt-capable ports on your devices.

If you have any questions or require assistance, please reach out to us at team@duetdisplay.com - we're happy to help!