I have the older model of your media center, so i am not sure this applies to your RHR 730n
Mine is the RER 730n, the 3 letters are found on the radios face, lower right hand corner
When you have your NAV map on your screen
press the the talking face button, it is the uppermost hard key on the right side, just above the phone button.
This will give you several options, it works like using your cell phone devise, close your windows & put your climate control fan in the lowest position or turn it off.
I practiced it a few times while i was parked, so i knew what was happening, my radio sometimes irritates me, because it sometimes gets my oral directions confused.
Something else that you should know, once the womans voice starts reading the options, you can make it stop, by pressing the talking face button again, then make your choice
2009 Ram 1500 SLT QC, HEMI , 3.55 axle, Bushwacker flares, soft tonneau, Line_X, DEBO Step, Mag-Hytec, Weathertech mats
2016 Ram 3.0 diesel 3.55 w/LSD, G2 tonneau, Line-X, Weathertech mats, Mag-Hytec differential cover, Nfab bars, CB radio, Autonet wi-fi router, EGR bug deflector