i found this for the RER radio the RHR radio is done the same way
Now available for you 2011-2012 Dodge Ram (see list) owners that have upgraded to the uconnect gps (RER) mygig touchscreen radio. Now with this wiring kit you can connect your existing microphone mirror to your newly added RER mygig radio, which will enable hands-free calling, and voice control of the radio.
this member made the swap that you are making
If you don't have the REAR VIEW MIRROR with the dual microphones
you can run this microphone & wiring up the drivers door post & mount it there, it is the same one that they use in Jeep vehicles with your new radio
from what i have read, the smaller GREY connector in the center is part of microphone set up