1. Connect the remote cable as shown in the diagram below:
2. Connect the PWM servo plug into an available PWM channel(e.g. CH5 corresponds to switch SA) of your PWM receiver. Take FrySky X9D as an example, you can set CH5 as switch SF on INPUTs page.
3. Set in the OSD Menu:
General > Control Mode > [PWM]
4. Quit OSD Menu and power off.
5. Power on the camera and use your pre-set switch(e.g. SA) to control your camera:
Toggle rapidly twice is to change video/photo mode, toggle once is to start/stop recording or take photos.
Shouldn't the white wire from the PWM connection board go to the RX pad rather than the TX pad?
That would make more sense for an input signal to go to RX.
After some experimentation it seems the TX pad is the correct one to use when the control mode is set to PWM. Nothing happens if you use the RX pad.
I can now successfully toggle the video recording on and off. Plus switch to the still capture mode. The latter is a bit terrifying for FPV as it temporarily freezes the image with what was captured. Leaving you flying blind for a bit.