The receiver has been in the cab in trimble for many years the EZ-Guide plus, 250, 500, cfx 750, fmx 1,000 and the tmx are all in the cab. The antenna that receives the sat signal is on the roof it is just a antenna no brains on roof to get wet or busted up in a storm or low door. The anemia on the roof is hooked to the display that's in the cab that has the gps receiver via a coax cable. Whats different about the the TMX is the display is now basically just a android tablet that hooks to what is called the tm200 via a ethernet cable the tm 200 has the gps receiver now that is also mounted in the cab then once again a coax cable is sent outside onto the roof to a antenna that receives the satellite signals.