Hi, I bought Turnigy Aerodrive DST-1200 Brushless Outrunner motor 1200kv from Hobbyking.  I found that this motor is running in clockwise direction.  I want it to rotate in Anti-clockwise direction.  I know if I change two last wires can reverse the motor.  But I want to know is it possible to reverse rotation of motor by using transmitter.  Please enlighten me.  I am using turnigy 9x transmitter

Thanks in advance

No, not possible via the TX.

not possible with transmitter but one can use car esc with forward and reverse. (might work, depends on motor).

well you can reverse rotation while flashing new firmware - you have to assemble the hex file
yourself making the appropriate edits in the asm file. Incidentally you can also make a normal esc
into a car type esc with reverse enabled.

I am only talking about the common simonk firmware. I have no experience with BL heli or the newer oneshot.

Okay, now I'm interested too! Are there any links that tell you how to do that step-by-step?

http://wiki.openpilot.org/display/WIKI/How+to+Flash+ESCs

Aren't there any pre-assembled hex files with reverse feature?

preassembled hex files - on a hit or miss trial is not advisable .

you can burn up your esc if the file contains the wrong timing and fet information.

better read up on how to assemble your own hex files and enjoy total liberation.