SuperSocket.SerialIO

var host = SuperSocketHostBuilder
    .Create<StringPackageInfo, CommandLinePipelineFilter>()
    .UsePackageHandler(async (s, package) =>
        {
            await s.SendAsync(Encoding.UTF8.GetBytes(package.ToString() + "\r\n"));
        })
    .ConfigureSuperSocket(options =>  
        {
            options.Name = "SIOServer";
            options.Listeners = new[] {
                new SerialIOListenOptions()
                {
                    PortName = "COM2",   // serial port name
                    BaudRate = 9600,  // baudRate of the serial port
                    Parity = Parity.None,
                    StopBits = StopBits.None,
                    Databits = 5;  // value limit 5 to 8
                }
            };
        })
    .UseSerialIO()
    .ConfigureLogging((hostCtx, loggingBuilder) => {
        loggingBuilder.AddConsole();
    }).Build();

{
    "serverOptions": {
        "name": "SIOServer",
        "listeners": [
            {
                "path": "sio://COM1/?BaudRate=9600&Parity=Odd&StopBits=2&Databits=7"
            }
        ]
    }
}