Icom Ci V Usb Interface Schematic Top -

[ PC USB-TTL Side ] [ Icom Radio Side ] TXD o----[ 470 Ohm ]----+ +----o CI-V Tip (Data) | | +-----+ +-----+ | LED | | Photo| +-----+ |Trans| | +-----+ GND o-------------------+ | +----o CI-V Sleeve (GND) RXD o-------------------+ +----o CI-V Tip (Data) | | +-----+ +-----+ |Photo| | LED | |Trans| +-----+ +-----+ | VCC o----[ 4.7k Pull-up ]+ +----[ 470 Ohm ]---o CI-V Tip (Data) Use code with caution. How it works: This circuit uses two optocouplers (e.g., or 4N35 ).

: Solder the 1N4148 diode and 10k resistor between the TXD and RXD pins as specified in your chosen schematic to create the single-wire bus. Wire the 3.5mm Jack Connect the of the 3.5mm mono plug to the combined TXD/RXD line. Connect the to the GND pin of the USB module.

When designing the printed circuit board (PCB), the layout of the top layer must prioritize RF noise mitigation and user clarity. Top-Layer Component Placement

The protocol is a form of , a method similar to how devices communicate on an Ethernet network. On a CI-V bus, any device (a transceiver, a computer interface, an antenna tuner) can attempt to transmit data. If two devices transmit simultaneously, a collision occurs. The devices detect this, stop transmitting, wait a random amount of time, and then retry. This multi-master architecture is what allows multiple pieces of equipment (up to 4 on a simple bus) to be daisy-chained together and controlled over a single wire.

The bus operates at standard 5V or 3.3V Transistor-Transistor Logic (TTL) levels. icom ci v usb interface schematic top

This circuit uses a dedicated USB-to-UART bridge IC, followed by optocouplers to completely isolate the computer's electrical ground from the radio's ground. Component List

By understanding the electrical requirements of the CI‑V bus and by building a design that respects the need for bus buffering and proper power delivery, you can create an interface that will serve you for years. Whether you choose a simple discrete‑transistor circuit, a MAX232‑based design, or a modern USB‑to‑TTL solution with a 7417 buffer, the sense of achievement when you first change frequency from your logging program is well worth the effort.

Connecting your Icom transceiver to a computer opens up a world of automated logging, digital modes, and rig control through software like Ham Radio Deluxe, WSJT-X, or fldigi. Icom radios use a proprietary communication protocol called CI-V (Computer Interface Five). While commercial cables are cheap, building your own CI-V to USB interface is an excellent afternoon project that helps you understand the hardware layer of your shack.

+---------------+ | USB Port | +---------------+ | | v +---------------+ | FTDI Chip | | (FT232RL) | +---------------+ | | v +---------------+ | Voltage | | Regulator | +---------------+ | | v +---------------+ | Interface | | Circuit | +---------------+ | | v +---------------+ | Radio | | Interface | +---------------+ [ PC USB-TTL Side ] [ Icom Radio

Let’s expand into a real component-level schematic. This is the found in Icom CI-V interfaces (e.g., the “RA0SMS CI-V” design or the “K8ZTT USB-to-CI-V”):

Place a signal diode (1N4148) on the TX line (cathode towards the plug tip) to allow the RX line to read the bus without interference. Pro Tips for Builders G3VGR's USB CI-V and Winkey Interface - QSL.net

This article covers the essential schematics, component choices, and top interface options. 1. What is the Icom CI-V Interface?

There are several approaches to designing a CI-V interface. Here are the top, proven schematics you can build. A. The FTDI232RL Based Interface (High Reliability) Wire the 3

Prevents ground loops and RF feedback between the PC and the transceiver. The Top Schematic Design

If you are searching for "icom ci v usb interface schematic top", you are probably looking for a clear diagram of a that includes the correct bus driver, not just a UART‑to‑CI‑V connection sketch. The G3VGR design—or a modern variation using a CP210x board with an external 7417—is an excellent starting point.

One builder reported that their simple two‑transistor interface worked perfectly on a native COM port but failed when used through a USB‑to‑serial converter; the problem was insufficient power available on the modem control lines. The solution was to either reconfigure the interface for external power or use a different USB‑to‑serial adapter.

: If using a pre-made CP2102 or FT232RL breakout board, identify the Solder the Bridge