Icom Ci V Usb Interface Schematic Top Today

+---------------------+ | USB Connector | +----------+----------+ | +----------v----------+ | USB-to-Serial IC | | (FT232RL / CH340) | | - TTL Out (TxD) |---(0/3.3V)---+ | - TTL In (RxD) |<--(0/3.3V)---+ +----------+----------+ | | | +----------v----------+ | | Logic Inverter | | | (Transistor/NAND) | | +----------+----------+ | | | +----------v----------+ | | Bidirectional | | | Buffer / Open- | | | Collector Driver |<-------------+ +----------+----------+ | +----------v----------+ | CI-V Connector | | (3.5mm stereo or | | 2-pin phoenix) | +---------------------+

Connect from the FT232RL to Pin 8 (VCC) and Pin 7 (Enable) of IC 3 (6N137) . Place a 0.1 F capacitor (C1) between Pin 8 and Pin 5 (GND) of IC 3. Connect RXD from the FT232RL to Pin 6 (Output) of IC 3 . Install a 10

Because the FTDI chip outputs separate TXD and RXD signals, they must be combined into the single-wire CI-V topology on the radio side of the optocouplers.

Connect from the FT232RL to the cathode (Pin 3) of IC 2 .

Requires a separate USB-to-Serial converter board. B. The FTDI FT232RL Interface (Reliable & Robust) icom ci v usb interface schematic top

Type-B USB chassis mount (or tethered cable) and a 3.5mm mono jack. The Master Interface Schematic

Acts as an open-drain/open-collector drive, pulling the data line down to 0V when transmitting, and releasing it high (via a pull-up resistor) when idle. Pull-up Resistor: A resistor connected to

This is where many commercially available USB-to-Serial cables fail. The CI-V bus operates at , not the ±12V levels of RS-232 or the 3.3V levels of many microcontroller boards. The signal logic is as follows: Install a 10 Because the FTDI chip outputs

: Because the radio operates on a shared "open collector" bus, the schematic usually includes a diode (like a ) or a buffer (like a

A high-speed digital isolator that isolates the TX and RX lines cleanly up to 150 Mbps.

FTDI FT232RL or CH340K breakout board (outputs TTL-level TX/RX). Optocouplers: (2) 6N137 or 4N35 high-speed optocouplers. Diodes: (1) 1N4148 fast switching diode. Resistors: (2) 1kΩ, (1) 4.7kΩ, (1) 10kΩ.

(Invoking related search suggestions...) Resistors: (2) 1kΩ

Because the USB bridge separates data into distinct TXD and RXD pins, you must combine them into the single-wire CI-V line without causing data collisions or looping your own transmissions back into the computer blindly (though the CI-V protocol natively expects to "echo" transmissions back to the controller). Optoisolation (Highly Recommended)

For a reliable "top-tier" homebrew design, using a dedicated USB-to-TTL serial chip like the is highly recommended. ICOM CI-V - K7MEM

A direct USB-to-serial chip (like FT232 or CH340) outputs . The Icom CI-V bus operates at:

If you are building or buying such an interface, here is what the schematic tells you about performance: