Bluetooth serial communication - serial port transparent transmission

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Hi,

I two devices Bluno nano(arduino Uno) and Bluno Link (Bluetooth dongle) just to give a reference to the hardware. I am able to establish the connection between them and can monitor the data through the arduino serial monitor (just connect both of them to different pc's). I also got this piece of code online and it is working as expected (can read and write data).

But it is also mentioned in one of the ROS answers that using rosserial is more reliable. So when i ran

$ rosrun rosserial_python serial_node.py _port:=/dev/ttyACM0 _baud:=115200
[ERROR] [1525425583.457823]: Creation of publisher failed: unpack requires a string argument of length 2
[ERROR] [1525425598.423438]: Lost sync with device, restarting...

This my running on Bluno nano (arduino Uno)

void setup() {
  Serial.begin(115200);  //initial the Serial
}

void loop() {
  if (Serial.available())  {
    Serial.write(Serial.read());//send what has been received
  }
}