How to achieve hardware exposure synchronization between Gemini 336 and USB Type-C Gemini 305?

[yang-si-hang]

Hi Orbbec team,

I am trying to synchronize the RGB exposure timing between a Gemini 336 and a Gemini 305 (USB Type-C version) for a multi-camera robotic data acquisition setup.

According to the documentation:

• Gemini 336 supports hardware synchronization through its dedicated 8-pin sync port, which can be connected to a Multi-Camera Sync Hub.
• For the USB version of Gemini 305, the hardware synchronization signal is located on pins A8/B8 of the USB Type-C interface, and the documentation mentions that the USB cable harness needs to be modified.
• The Gemini 305 documentation mainly describes connecting these synchronization signals to an SoC or MCU.

I also have an Orbbec Multi-Camera Sync Hub Pro, but I do not see a direct way to connect the USB Type-C Gemini 305 to the Sync Hub, since the Gemini 305 does not have a separate 8-pin synchronization port.

My intended setup is approximately:

Gemini 336 (Primary)
        |
     8-pin sync
        |
Multi-Camera Sync Hub Pro
        |
        ?
        |
Gemini 305 USB Type-C (Secondary-Synced)

The goal is to achieve actual frame/exposure synchronization, rather than only timestamp synchronization.

I have already tried synchronizing the device timestamps in software. The timestamps can be brought onto a comparable time base, but because both cameras are free-running, their actual exposure timing still drifts relative to each other.

I also experimented with SOFTWARE_TRIGGERING, but it has not provided a reliable solution for our continuous data acquisition use case. Therefore, I would prefer to use the supported hardware synchronization mechanism if possible.

Could you please clarify:

1. What is the officially recommended way to hardware-synchronize a Gemini 336 with a USB Type-C Gemini 305?
2. Is there an official USB Type-C breakout/sync cable or adapter for Gemini 305 that exposes the A8/B8 synchronization signal and can connect to the Multi-Camera Sync Hub Pro?
3. If no such adapter is available, could you provide the recommended wiring/pinout for connecting the Gemini 305 A8/B8 synchronization signal to the Sync Hub?
4. Does this configuration require an external MCU/SoC, or can the synchronization signal from the Gemini 336 / Sync Hub directly drive the Gemini 305?
5. If hardware synchronization between these two models is not currently supported, is there another recommended method to achieve stable exposure synchronization between Gemini 336 and Gemini 305?

Thanks!