"Unfortuantely this is not true. None of the RTK units on the market currently can use another mfg base station. One issue is the format that they transmit in, and the second is the frequency that their radios broadcast on."
 

We are running a Trimble 252 on RTK from a CORS station that is using a Lecia receiver.  We are using cell phones to transmit the signal.

Also, it has be stated that RTK uses 2 way signals between the rover and base.  I believe this is incorrect also.  I don't think there is any communication from the rover to the base in RTK.