no permission to read or write this serial port

[SArrueLorca]

Hi. I'm trying to create an app that uses a COM port to send strings to a laptop. So, i was compiling my app on react native with a Windows OS and everytime that i want to use an specific port (COM3 in this case) in the function "const serialPort = await SerialPortAPI.open("/dev/ttyS4", { baudRate: 9600 });" i get the "no permission to read or write this serial port" error message.

I tried to mitigate the error putting the following permissions in my android manifest: INTERNET, WRITE_EXTERNAL_STORAGE", READ_EXTERNAL_STORAGE and USE_PERIPHERAL_IO"

And the following static function in my "App.js", considering the closed issue #9, to no avail
static setSuPath(suPath) {
SerialPortAPI.setSuPath("/system/bin/su");
}

I would like some help on how to fix this error please

[SArrueLorca]

Also. Considering this similar package: https://github.com/licheedev/Android-SerialPort-API/blob/master/README.md
Do i have to root my phone/tablet to make it work?

[bastengao]

You could just call SerialPortAPI.setSuPath("/system/bin/su") if su path is /system/bin/su, don't need to define static function setSuPath.

[SArrueLorca]

Great, i called setSuPath and open in a function called by the constructor. Now about the su path, how do i get it if the default one (/system/bin/su) didn't work?. Do i have to root my phone to do so?

[bastengao]

https://developer.android.com/studio/command-line/adb#shellcommands

Go into shell on Android phone, then execute which su, you will get su path.

[alisaya10]

hi dear i have the same issue too i do some stuff like bellow but still give me the no permission to read or write this serial port

i put this lines to androidManifest.xml

<uses-permission android:name="android.things.permission.USE_PERIPHERAL_IO" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

get /system/xbin/su from command ( which su ) and put this to following code

 async function example() {

        SerialPortAPI.setSuPath("/system/xbin/su");
        console.log("tp1")
       
        const serialPort = await SerialPortAPI.open("/dev/ttyS2", { baudRate: 38400 });

        // subscribe received data
        serialPort.onReceived(buff => {
            console.log(buff.toString('hex').toUpperCase());
        })

        

        // unsubscribe
        // sub.remove();

        // send data with hex format
        await serialPort.send('00FF');

        // close
        serlialPort.close();
    }
    example()

please help thanks

[rinshadkk]

i am still getting the permission error. @alisaya10 Did you get it resolved?

[Ranjit8298]

Hii @rinshadkk , Did you get it resolved the issue?

[MelihaDuman]

hey any update on this issue? I am facing the same.