(Or maybe just waifu bartending, whatever floats your boat.)
(Or maybe just waifu bartending, whatever floats your boat.)
For further reading, search for “Icom CI-V specification document” (Icom publishes the electrical spec) and open-source designs like “USB-CI-V by YO3FVR” or “W6IPA CI-V interface schematic.”
Connect the anode of the diode to the RXD pin using a small piece of hookup wire.
Usually auto-sensing, but commonly set to 9600 or 19200 bps in software. Uses Hexadecimal framing starting with "FE FE" (Attention). CI-V Communications Interface-V, Reference Manual 3.2
| Requirement | Why it matters | |-------------|----------------| | | CI-V is a shared bus; multiple devices can drive it low. A standard totem-pole output would short-circuit. | | Pull-up resistor (~4.7kΩ) | Ensures CI-V line idle high without current drain. | | Diode protection | Prevents CI-V voltage (5-12V accident) from back-driving FTDI chip. | | No ground loops | The interface should have opto-isolation (advanced) or at least common ground – but a direct ground is acceptable for single radio. | | Inversion as per Icom spec | Without correct inversion, commands will be byte-swapped or corrupt. |
When looking at a schematic, these elements ensure your interface works. icom ci v usb interface schematic top
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.
Both the transceiver and the computer pull the line to ground (0V) to transmit data bits. This prevents damage if two devices attempt to transmit simultaneously.
: Because the CI-V bus is a single-wire system, the unidirectional TX and RX lines from the chip must be combined. This is often done using:
I couldn’t find a specific top-level schematic titled exactly “ICOM CI-V USB Interface Schematic Top” in public databases. However, the is ICOM’s proprietary control bus for radios (e.g., IC-703, IC-706, IC-718, IC-7300, etc.). A typical USB-to-CI-V interface uses a USB-to-serial bridge chip (FT232RL, CP2102, CH340) combined with a level converter (since CI-V is TTL-level, not RS-232). For further reading, search for “Icom CI-V specification
Connect from the FT232RL to the cathode (Pin 3) of IC 2 .
For a robust USB‑based CI‑V interface, you will need:
Requires a separate USB-to-Serial converter board. B. The FTDI FT232RL Interface (Reliable & Robust)
. These chips handle all USB protocol tasks and provide TTL-level Transmit (TX) and Receive (RX) signals. CI-V Communications Interface-V, Reference Manual 3
pull-up resistor (R3) between Pin 8 (VCC) and Pin 6 (Output) of .
Building a USB CI-V interface generally involves three main functional blocks: G3VGR's USB CI-V and Winkey Interface - QSL.net
The well‑known follows the MAX232 principle: a level converter that accepts RS‑232 from a computer and produces TTL for the CI‑V bus. The official Icom schematic is a good reference point for a proper implementation.
levels, which will damage the radio's logic circuits. A converter (interface) is required. 2. Top DIY CI-V USB Interface Schematics