Several asked me recently about the advantages of using the built-in Spektrum technology (such as in the 9303 2.4Ghz or Spektrum Dx-7, vs the use of an add-on or aftermarket 2.4Ghz module. In addition to having 2x resolution of the built in Spektrum compared to using the add-on or aftermarket 2.4Ghz module- Here is another big advantage. How many times have you turned on your plane having forgot to swich model memory, went to start the motor and realized you were on the wrong model (sometimes with the upleasant suprise of the model being at full throttle when you start). Well the built in Spektrum technology is set up to that exact model, making it impossible for this situation to happen. Any case here is the excurpt:

ServoSync and ModelMatchβ€”Extra Safety and Precision:
DSM2 and the AR7000 aren’t the DX7’s only marvels.Spektrum engineers have come up with two more patent-pending innovations that you’ll wonder how you ever lived withoutβ€” ModelMatchβ„’ and ServoSyncβ„’. ServoSync is an ingenious new feature that actually resequences the bits of data the DX7 transmits based on the type of mixing you select. So, if you have a dual elevator on your big Extra or a 3-servo CCPM setup on your heli, ServoSync will see to it that those servos working together receive their impulses together. The result is more synchronized servo movement that translates into an undeniable, locked-in feel when you fly. ModelMatch puts an end to the β€œwrong model” syndrome. Almost everyone who flies RC has at one time or another crashed because he neglected to verify the model name on the transmitter display in his preflight check. A unique code is embedded in the DX7’s signal so that, if the wrong model’s name is on the screen, the model’s controls simply won’t respond.

More details at http://www.horizonhobby.com/Products...ProdID=SPM2710