Error writing 337 bytes at offset 0 length=337

Hey, I’m trying to write something from my android app to the payment terminal iWL250. Application should send json with data and then terminal prints something.

serial.requestPermission({
                vid: '079B',
                pid: '0028'
            },
                function (successMessage) {
                    serial.open(
                        { baudRate: 57600 },
                        function (successMessage) {

                            serial.writeHex(
                                JSON.stringify(text),
                                function (successMessage) {
                                    $cordovaToast.showLongBottom(succesMessage);
                                    alert(successMessage);
                                },
                                errorCallback
                            );
                        },
                        errorCallback
                    );
                },
                errorCallback
            );

application connects to the terminal, but when it tries to write data I get an error: “Error writing 337 bytes at offset 0 length=337”

[ghost]

How to change the endpoint as mentioned above ?

[sureshkumar-s89]

I used this (https://play.google.com/store/apps/details?id=aws.apps.usbDeviceEnumerator&hl=en) android app to get information of connected device. Here I have attached the screenshot (DeviceInfo.zip) of my weight scale device info using this app.

I found that it has five interface of which two are CDC class and both have two Endpoints. Does it causes any problem? I don’t know whether this information is useful.