Icom Ci V Usb Interface Schematic
+5V (from USB Vbus) | R1 (4.7k) | +--------> To Icom CI-V Data Pin (Center pin) | | USB Port FT232RL Level Shifter Icom Radio (PC Side) (U1) (Q1, Q2) (J2) -------- ------ -------- ------ Vbus ---[R4]-------> VCC (5V) | D- ---> USBDP TXD (Pin 1) --------R2-----> Base Q1 | D+ ---> USBDM RXD (Pin 5) <--------|----- Collector Q1 | GND ------------> GND Emitter Q1 -----+--> CI-V Data | Optional: Use RTS & DTR pins for DTR/RTS control (PTT)
| Problem | Likely Fix | |---------|-------------| | No communication | Swap TX/RX; check baud rate match | | Radio locks up | Add opto-isolation; check pull-up resistor | | Intermittent control | Add ferrite beads on USB cable | | Works then stops | Ground loop – ensure only USB side grounded to PC | | CI-V bus conflict | Change radio’s CI-V address (default 94h for Icom) | Icom Ci V Usb Interface Schematic
Search these terms (ham radio safe sites): +5V (from USB Vbus) | R1 (4
USB Port │ ┌────┴────┐ │ CH340G │ │ USB-UART│ └────┬────┘ │ ├── TXD ──────► (to opto-isolator input) │ ├── RXD ◄────── (from opto-isolator output) │ └── GND ──────► (common with USB side only) VCC (5V) | D- --->