Frame syncing from external signal

We recently bought 3 StellarHD cameras and would like to synchronize them by providing an external trigger. We tested the sync between cameras by connecting the FSIN wires together in Leader-sollower mode. |
In order to provide a external clock signal, we could not find documentation on the page here: Frame-Syncing Multiple Cameras - Starter Kit.
Would be great if you could update the page with some pin diagram or voltage specs.

Thank you,


The specific voltages are on the product page.

Hope this helps!