Use the CI-V address and serial speed configured in your radio. A4h / 115200 is an example for IC-705.
Warning: CI-V commands may change radio settings. Check your radio's manual before sending commands. Use at your own risk.
Command
Enter a HEX command (e.g. 03 to read frequency or 07 B0 to switch VFO A/B). Short commands are automatically wrapped with the selected CI-V address. Complete packets (FE FE … FD) are sent unchanged. Supported commands depend on the radio model.