Icom Ci V Usb Interface Schematic Top |top| [Best Pick]

: Always download the specific Icom USB drivers or the drivers for your specific serial chip (FTDI, CP2102) before connecting the hardware to your PC.

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

: The CI-V (Computer Interface 5) protocol uses a bi-directional, single-wire TTL signaling system where a single "DATA" line is held high until a device pulls it low to initiate communication. USB-to-Serial Conversion

: If building your own, ensure you install the appropriate Virtual COM Port (VCP) drivers from the chip manufacturer (e.g., FTDI ) to allow software like Ham Radio Deluxe or FLDigi to communicate with the rig. Explore USB with this USB to CI-V Interface - N5DUX icom ci v usb interface schematic top

Connect Pin 6 (Output) of to the cathode (striped side) of the 1N4148 diode (D1) . Install a 10

Because CI-V is a "half-duplex" single-wire system (the radio and the computer take turns talking on the same wire), you cannot simply tie the TX and RX pins directly together without risk of contention. However, with FTDI chips, there is a trick:

Enter your Icom radio's internal menu system. Ensure CI-V Baud Rate is set to "Auto" or match it exactly to your PC software (e.g., 19200 or 9600 bps). Take note of your radio's CI-V Address (e.g., 94h for the Icom IC-7300). : Always download the specific Icom USB drivers

Manhattan-style (or "dead bug") construction is excellent for prototyping, as suggested by KA6WKE .

: A resistor (often around 4.7kΩ to 10kΩ) pulls the DATA line high when idle. Isolation & Protection : USB-to-Serial Conversion : If building your own, ensure

The TXD pin connects through a 1kΩ current-limiting resistor to the anode of the internal LED inside the first optocoupler.

: Download a reference schematic from reputable ham radio sites (e.g., G4ILO’s interface, K0GW’s CI-V adapter), open your preferred PCB software, and build the interface that will sit at the top of your radio desk for years to come.

: It utilizes a CSMA/CD system to manage traffic on the shared bus, ensuring over 90% bus efficiency. Schematic Topography and Key Components

Alternatively , a separate isolated DC-DC converter (e.g., B0505S) can generate a floating 5V for the radio side, eliminating the need to draw power from the radio.

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).