Connect all PC-side grounds together: FT232RL GND, Pin 5 of IC 2, and Pin 5 of IC 3. Step B: Wiring the Radio Side (Isolated Domain)
CAT (Computer Aided Transceiver) is a generic term for computer control of a radio. CI‑V is Icom's specific implementation of a CAT system. Other manufacturers (Yaesu, Kenwood, etc.) use their own protocols, although many modern radios from all brands have similar physical‑layer characteristics. icom ci v usb interface schematic top
PC SIDE (USB Powered) RADIO SIDE (Radio Powered) --------------------- ------------------------- TXD ---> [ 6N137 Opto 1 ] --------> Combined CI-V Bus (Tip) RXD <--- [ 6N137 Opto 2 ] <-------- Combined CI-V Bus (Tip) GND_USB GND_RADIO (Sleeve) Use code with caution. 3. The CI-V Combining Network (The "Top" Schematic Logic) Connect all PC-side grounds together: FT232RL GND, Pin
While commercial cables exist, building your own CI-V to USB interface is an excellent, low-cost weekend project. This guide provides a highly efficient, field-tested schematic design to link your Icom rig to any modern USB port. Understanding the CI-V Hardware Protocol Other manufacturers (Yaesu, Kenwood, etc