bern said:
Videothis: I have just received this identical transmitter. As you have also discovered, there are no instructions with this unit. Have you successfully hooked it up yet? I thought I'd ask before I start an extensive experimentation program.
You're in for some soldering -- I'm not aware of anyone making a custom cable for this yet.
Short answer, using the DJI-supplied 3-wire cable that comes with the upgrade board:
Yellow wire on the DJI cable -> VID (yellow wire on Immersion 5-pin cable)
Brown wire on DJI cable -> GND (black wire on the Immersion 5-pin cable)
Red wire on DJI cable -> NOT USED (but see below...)
I recommend you don't power the Immersion from the DJI 3-pin cable because the wires are very small and the Immersion draws a fair bit of current. Since the upgrade board doesn't have the AUX power leads that come on the original main board (that little gray/red wire that was originally tucked into the white grommet between the landing strut screws), you have a few options:
1) Resolder that old AUX power lead onto the upgrade board (connect to any GND and Vcc pads, e.g., where the battery leads are soldered in or to any ESC pads) and put a JST connector on it so you can plug it into the power cable that comes with the Immersion.
2) Cut the red JST connector off the Immersion power cable and solder red and black directly to the main board. Plug the other end into the Immersion 2-pin power jack.
3) (not recommended) Run the RED wire from the DJI 3-pin video out to the BATT (red) wire on the Immersion 2-pin power connector and tie the black wire on the Immersion 2-pin to the brown wire you've already connected to the other GND (black) line on the Immersion 5-pin. (All three grounds are tied together.) But as I said, not recommended due to a lot of power draw across very fine wires.
I think it would be the best investment possible for DJI's customer service reputation if they'd spend $500 on a temp or college student who could write well and make the translations clear. But what do I know? 
