Icom Ci V Usb Interface Schematic Top Review

A very specific topic!

3.3 Buffer Driver (Open Collector Output)

CI-V requires an open-collector driver.

[USB Port] → [USB-to-UART bridge] → [Opto-isolation stage (TX direction)] → [Buffer/Driver] → [CI-V connector (3.5mm TRS)]
                                                    ↑
[CI-V connector] → [Signal conditioning] → [Opto-isolation stage (RX direction)] → [UART RX]

• Direct TTL-level interface (for radios exposing TTL CI-V).
• RS-232 level conversion (for older radios with 3.5mm mono jack using ±V levels) — avoid unless required.
• USB-to-TTL serial adapter (FTDI, CP2102, CH340) is the easiest modern solution; set adapter to 19200/1200/lowest as required by radio.

. These chips convert USB data into standard asynchronous serial signals. icom ci v usb interface schematic top