Here’s the module taken from the MLP4DSM transmitter that comes with E-Flite RTF kits. It shows the wiring necessary for hookup to the Turnigy 9x running custom firmware that supports the DSM2 protocol.

See this post for location of the 3.3v pad to solder the red wire to.

I added an LED inline with the PPM signal wire. Because the LED is a diode, it drops the voltage of the PPM line from 5v to the 3.3v that the DSM2 module can handle.

To protect the entire assembly, I used 1/2″ clear shrink tube. The clear shrink tube allows me to see the status LED onboard the DMS2 module.

Everything is working great with the latest th9x firmware. I was able to bind to my mSR by holding the trainer switch while powering up the transmitter.

On the er9x front. Mike Blandford was able to get the th9x source code properly added to the er9x firmware. Use build r635 or later. I was successful in using his firmware in connecting the Turnigy 9x TX to the mSR. Great job Mike!

*04/23/2012 Update*
This setup continues to work without a hitch for me. I have since bound to and controlled the following Blade models successfully: mCX2, mSR, mCP X, 120SR and mSR X.