Will the adapter (the cord which connects the transmitter to the device which is inserted into the usb port on the computer) for the Phoenix simulator, work with the Reflex XTR system?

Is there a source, other than MRC, for the adapter to be used with Reflex?

In one word, NO.
The Reflex slim stick is the Reflex security key. It is their guarranty that no one can get a stick and just use someone elses program disk, and they do not sell them - stand alone.
The only way to get one is to buy the whole program or request a new (which means sending in the old damaged broken one). If you loose it, you are out of luck!

Thank you.

I purchased from MRC and had severe problems getting the program to start.
After call, email and letter, was promised a replacement stick, after I returned the one I had. Assured a new one was in stock and turn around would be only five days or so.

After two+ weeks I emailed, and was told a stick had been sent. Same problem.

Only later did I learn they simply sent back the one I had trouble with! Not surprisingly, it worked no better despite the wasted exercise of two mailings.