Icom Ci V Usb Interface Schematic Top !!better!!

Connect a wire from the terminal of the jack directly to the RXD pad on the USB module (the same pad where the diode's anode is attached).

The critical point often omitted in simplified "USB to CI-V" diagrams is . Because CI-V is a shared bus, multiple devices can transmit on the same pair of wires. In practice, this means the TX line from the UART cannot be connected directly to the radio's REMOTE tip. Instead, a buffer IC such as the 7417 hex buffer must be placed between the UART and the CI‑V bus to emulate an open‑collector output.

Combine the separate TX and RX lines into a single, bi-directional 3.5mm mono line without causing data collisions. The Core Schematic Components

Check for TX and RX swapped at the transistor level.

This chip is entirely powered by the 5V VBUS wire from the computer's USB port. icom ci v usb interface schematic top

Each has its own schematic variations, but they all aim to satisfy the same requirements.

: Ferrite beads and small bypass capacitors (e.g., 0.01 µF) are often added to the data lines to prevent radio frequency interference from disrupting the connection. Typical Circuit Layout Key Design Considerations

Asynchronous serial, 8 data bits, no parity, 1 stop bit (8N1).

Some Icom radios include an internal pull‑up. However, to guarantee reliable operation with any radio or any cable length, adding an external 4.7 kΩ pull‑up to +5 V is a wise precaution. Connect a wire from the terminal of the

If you choose to etch your own PCB or build this on a prototyping perboard, . Keep all copper traces on the USB side at least 2mm away from all copper traces on the Radio side. Do not bridge the grounds under the optocouplers; keeping them separate is the entire purpose of an isolated schematic. Software Configuration

Before building an interface, it is crucial to understand the physical and electrical nature of the CI-V bus itself. Icom designed it to be a multi-drop bus, meaning a single line can connect several radios and controllers simultaneously, similar to a miniature local area network. The official Icom CT-17, for example, features four parallel 3.5 mm mono jacks for this very purpose.

CAT (Computer Aided Transceiver) is a generic term for computer control of a radio. CI‑V is Icom's specific implementation of a CAT system. Other manufacturers (Yaesu, Kenwood, etc.) use their own protocols, although many modern radios from all brands have similar physical‑layer characteristics.

The CI-V bus operates at standard standard 5V TTL logic levels. In practice, this means the TX line from

Enable the internal pull-up or solder a physical between the RX pin and the board's VCC (5V) pin. 2. Eliminating RFI (Radio Frequency Interference)

Controlling your Icom radio from a computer opens up a world of automated logging, digital modes (FT8, JS8Call), and seamless software-defined control. Icom uses a proprietary communication protocol called .

On most Icom radios, the CI-V port is a , typically labeled "REMOTE" . The connector has two conductors:

Building an Icom CI-V USB interface is an excellent weekend project that brings modern computer control to both vintage and new Icom transceivers. By following a reliable schematic utilizing an , you can ensure years of reliable operation for your CAT-controlled station.