The microphone can be connected direct to the Control-RRC AUX/MIC jack, if you have a mic with RJ-45 connector like the HM-103. The 3.5 mm plug is connected to the radio CI-V jack. The cable should have a 4/6 modular connector in one end and a 3.5 mm stereo plug in the other end. From the Radio-RRC:s TTL jack to the radios CI-V jack you need to make a simple cable.
When you want to control ICOM radios with the RRC-1258MkII via the CI-V protocol, you connect a standard RS-232 cable between the PC and the COM 2 connector on the back of the Control-RRC.
