Icom Ci V Usb Interface Schematic Top |link| Jun 2026

The DATA line is held HIGH (+5V) by a pull-up resistor.

CI‑V connector: Tip (data) ──┬─ 4.7k pull‑up to 5V or radio Vcc └─ drain of Q1 and 1k to RX Ring ──────── GND Sleeve ────── (optional +5V out) icom ci v usb interface schematic top

(typically 4.7kΩ to 10kΩ) is connected between the data line and +5V to maintain the bus in a high state when idle. Radio Side: A shielded cable terminating in a 3.5mm mono plug . The tip is the data line, and the sleeve is the ground. Simplified Wiring Diagram For those using a pre-made USB-to-TTL adapter (like those used for Arduino), the wiring is even simpler: Connect GND: Adapter Ground right arrow 3.5mm Plug Sleeve. Combine Data: Tie Adapter right arrow 3.5mm Plug Tip. Add Protection: The DATA line is held HIGH (+5V) by a pull-up resistor

Creating a USB interface for the Icom CI-V, a protocol used by Icom radios for computer communication, involves designing a simple interface that converts the CI-V's serial signal to a USB signal that a computer can understand. The CI-V protocol uses a 9-pin D-sub connector with a specific pinout and typically operates at 9600 bps. The tip is the data line, and the sleeve is the ground

The ICOM CI-V USB interface has numerous applications in amateur radio, including:

Searching for isn’t just about finding a random circuit diagram—it’s about understanding the topology that guarantees reliable, RF-immune computer control of your Icom radio. By following the principles and schematic blocks outlined in this article, you can build a professional-grade interface that outperforms many commercial units.