Where is the synchronous interface of the Jinbei photographic lamp 400 connected?

You can use the TR-A8 flasher of Jinbei to flash directly. The flasher consists of two parts. One part of the transmitter presses on the hot shoe of the camera, and the other part of the receiver presses on the synchronous socket of the video lamp. There is a flasher wire in each lamp. Now some cameras don't have that kind of socket. I suggest you use a flasher to flash.