Icom Ci V Usb Interface Schematic Top ((link)) Access

An optimized, modern DIY interface relies on three core sections: the USB UART chip, the steering diodes (or inverter logic) for the single-wire bus, and the physical RF decoupling components.

: A 7417 hex buffer or simple switching transistors (e.g., 2N3904) are frequently used to handle the open-collector drive. Popular Schematic Variations

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.

FTDI FT232RL or Silicon Labs CP2102. (A CH340G can also be used as a budget alternative). icom ci v usb interface schematic top

This public link is valid for 7 days and shares a thread, including any personal information you added. This link or copies made by others cannot be deleted. If you share with third parties, their policies apply. Can’t copy the link right now. Try again later.

Active Low. The line sits at 5V (high) when idle. An optimized, modern DIY interface relies on three

Draw a physical clearance gap (at least 2mm to 5mm wide) across the board. No copper traces, ground planes, or power planes should cross this line. The only components spanning this gap must be the physical bodies of the optocouplers.

Unlike standard RS-232 or TTL serial which uses separate Transmit (TX) and Receive (RX) lines, CI-V combines TX and RX onto a single bi-directional line.

Before diving into the USB interface schematic, it's essential to understand the ICOM CI-V protocol. CI-V is a communication protocol developed by ICOM, a Japanese company renowned for its high-quality amateur radio equipment. The CI-V protocol allows ICOM radios to communicate with external devices, such as computers, using a serial interface. This protocol enables features like remote control, frequency setting, and data transmission. CI‑V is Icom's specific implementation of a CAT system

Place 0.1µF ceramic capacitors directly across the VCC and GND pins of both the USB chip and the optocouplers to suppress high-frequency noise. Step-by-Step Schematic Connections Pin Connection From Pin Connection To USB Connector VBUS (+5V) FT232RL VCC / Opto 1 & 2 VCC (Host Side) Powering host electronics USB Connector FT232RL GND / Opto 1 & 2 GND (Host Side) Grounding host electronics FT232RL 6N137 (TX) Input Cathode Sending data to radio 6N137 (TX) Output Collector 3.5mm Mono Plug Tip (CI-V Bus) Driving the CI-V bus low 6N137 (RX) Input Anode 3.5mm Mono Plug Tip (via 1N4148 Diode) Reading data from CI-V bus 3.5mm Plug Sleeve (GND) Radio Chassis Ground / Opto Radio Side GND Grounding radio electronics PCB Design Layout Best Practices

CI‑V uses (one‑wire bidirectional data). The USB side (UART) is standard TTL (non‑inverted). So you need:

Ensure your software (e.g., HRD) uses the correct hex address (e.g., 94h for IC-7300, 4Eh for IC-706).

Unlike standard RS-232 or TTL serial interfaces that use separate Transmit (TX) and Receive (RX) lines, CI-V uses a single bi-directional line for data transfer.

Connect a 4.7kΩ to 10kΩ resistor between the CI-V Tip and the 5V VCC pin on the USB module to ensure the bus idles high. Key Components List USB-to-TTL Module: FTDI FT232RL modules are highly recommended for driver stability. Diode: or similar high-speed switching diode . Resistor: 4.7kΩ (standard for CI-V). Plug: 3.5mm (1/8") Mono Phone Plug. Cable: Shielded audio cable to prevent RF interference. Software Setup