Prior to the RHR FlexRadio architecture we ran on Elecraft K3's. Elecraft sold a remote head called the K3/0-Mini pictured above. When we made the transition to FlexRadio we added in support that allows the K3/0-Mini to control a number of Flex functions. This allowed our users who invested in the hardware while running on the Elecraft platform to continue using their investment on the new platform.
Selecting the correct COM port. You can see from the pull down menu showing the available COM ports that we "Recommend" the correct COM port to Select. In my example this is COM3.
K3/0-Mini shows "Connected".