Is there a recording start/stop flag embedded in the SDI signal of the F3?
My problem is that using a remote start from the focuspuller starts the camera but the external recorder is not. Using (last) TC is not an option for me because the filmcamera is synced to the audiorecording. So the cam is on 'free run' to maintain sync with the audio.
The BM hypershuttle has this functionality, however it doesn't work with the F3. (could be a BM thing ;-)

Yes the F3 sends it's own start/stop trigger down SDI. However, the menu function to turn it on isn't immediately obvious:
"Video Set - SDI Rec Control - HD SDI Remote I/F"
This works fine on my PIX240 with free-run timecode although I believe the recorder firmware had to be updated before it recognised the particular format of the Sony trigger. I abviously had to enable it on the recorder as well. Shame all the different manufacturers can't get in sync with this!

The trigger also works very well with my Samurai.

Also works with my PIX. Once its turned on in the menu that is.

Well, it doesnt work with the BM hypershuttle 2...
:-(
I also tried starting the F3 with a remote trigger