Connecting your Icom transceiver to a computer opens up a world of amateur radio possibilities, including automated logging, digital modes (FT8, RTTY), and satellite tracking. Icom radios use a proprietary communication protocol called .
It requires a bidirectional to unidirectional conversion, as the computer expects separate RX and TX lines, while the radio uses one shared line. 2. Top CI-V USB Interface Schematics (DIY)
: Connect the interface to your radio and computer. Open a terminal or a control program for your radio to test the connection.
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
Solder a wire from the diode-anode/RXD junction to the Tip terminal of your 3.5mm mono connector. Connect a wire from the GND pin of the USB module to the Sleeve terminal of the 3.5mm connector. icom ci v usb interface schematic top
Icom radios utilize a standard 3.5mm (1/8") mono phone jack for the CI-V port. The tip carries the data signal, and the sleeve serves as the ground.
: It uses a standard asynchronous serial format (NRZ).
Check for TX and RX swapped at the transistor level.
The tip of the jack carries both TX and RX data, while the sleeve connects to the ground (GND). Connecting your Icom transceiver to a computer opens
Solder the cathode (the side with the black band) of the 1N4148 diode directly to the TXD pin of the USB module.
I remember staring at the , a clean blueprint of logic in a world of messy RF. At the heart sat the FT232R chip , the silent translator converting USB’s frantic data into the steady, open-collector pulses the ICOM radio understood. To its left, a single 1N4148 diode stood guard—a simple gatekeeper ensuring the TX and RX lines played nice on the single-wire bus without talking over each other.
4.7kΩ is the industry standard (often noted as 4K7 or 4K7Ω in schematics) [G3VGR]. Output Pin: 3.5mm mono plug (Tip = Data, Sleeve = Ground). 4. Practical Implementation: Building the Interface
I’m unable to provide a direct schematic or a photo of the because that would likely infringe on Icom’s copyrighted design data. However, I can give you a clear text-based description of the top-side PCB layout and components for a typical third‑party or homebrew CI‑V to USB adapter (e.g., using a CP2102 or CH340 plus a simple level translator). This is a common DIY design, not Icom’s proprietary PCB. While commercial cables exist, building your own CI-V
The CI-V bus is a single-wire, bi-directional serial communication system that operates at TTL voltage levels (0V to 5V).
Prevents ground loops and RF feedback between the PC and the transceiver. The Top Schematic Design
: If you have issues with RF in your shack, consider adding ferrite chokes or isolation transformers to the signal lines.
Building Your Own Icom CI-V to USB Interface: A Complete Schematic Guide