Top — Icom Ci V Usb Interface Schematic

A robust DIY interface requires three functional blocks: a USB-to-UART serial converter, a bi-directional mixing circuit, and electrical isolation components. USB-to-UART Bridge

The radio side utilizes a standard 3.5mm mono phone jack . The tip carries the data signal, and the sleeve acts as the ground.

: If you have issues with RF in your shack, consider adding ferrite chokes or isolation transformers to the signal lines.

Once built, plug the interface into your PC. Windows, macOS, and Linux usually install FTDI or CH340 drivers automatically. icom ci v usb interface schematic top

Set both DTR and RTS to "Low" or "None".

Check your solder joints for bridge shorts. Wrap the entire assembly in clear heat-shrink tubing or mount it inside a small plastic project enclosure to prevent the bare components from shorting out against your radio chassis. Testing and Software Configuration

Solder the cathode (striped side) of a to the board's TX pin. A robust DIY interface requires three functional blocks:

This schematic uses the highly stable (or a pre-assembled FTDI/CH340 breakout board) alongside a simple diode-steering network. Required Components

: A resistor (often around 4.7kΩ to 10kΩ) pulls the DATA line high when idle. Isolation & Protection :

+5V (From USB) │ ├──────────┐ ▼ │ ┌───────┐ [R1] 4.7kΩ │ │ │ │ FTDI │ ├───────────────● Data (Tip) ──► To Radio │FT232RL│ │ │ (3.5mm Jack) │ │ │ D1 1N4148 │ │ TXD ├──────┼─────►|────────┤ │ │ │ │ │ RXD ├──────┴───────────────┘ │ │ │ GND ├─────────────────────────────────────► GND (Sleeve) └───────┘ Circuit Operation Explained : If you have issues with RF in

Once assembly is complete, plug the interface into your computer.

Icom’s official interface (e.g., or internal USB in IC‑7300/9700) is proprietary. You can:

lines are bridged to create the single-wire CI-V bus. A diode is placed between the cap T cap X

Connect all radio-side grounds together: , Pin 5 of IC 2, and Pin 5 of IC 3. Configuration and Software Setup

Before diving into the hardware components, it is critical to understand how the CI-V system transmits data.