Time stamping and synchronize the signal with external clock source with API

Quote from Sofon on 22/12/2021, 02:31

I want to mark the time stamping and synchronize the signal with external clock source with API program. Could you please explain for me what the difference of feature using the REF/TRG/PPM/GPS connector for V6, which one can be used for V6 clock souce ,which one can be use for time base,  which one can be used for time stamping?