sync rosserial arduino

edit

There was a couple of seconds a couple of seconds ago a question regarding rosserial arduino I accidentally deleted (I wanted to delete my own comment but accidentally deleted the entire question), sorry.

The issue was after running rosrun rosserial_python serial_node.py _port:=/dev/ttyACM0 the error unable to sync with device occurred.

The code looked quite like the example service client code but with a custom message (does not matter for the issue) and some parts commented out:

/*
 * rosserial Service Client
 */

    #include <ros.h>
    #include <std_msgs/String.h>
    #include <rosserial_arduino/Test.h>

    ros::NodeHandle  nh;
    using rosserial_arduino::Test;

    ros::ServiceClient<Test::Request, Test::Response> client("test_srv");

//    std_msgs::String str_msg;
//    ros::Publisher chatter("chatter", &str_msg);

//    char hello[13] = "hello world!";

    void setup()
    {
      nh.initNode();
      nh.serviceClient(client);
  //    nh.advertise(chatter);
      while(!nh.connected()) nh.spinOnce();
      nh.loginfo("Startup complete");
    }

    void loop()
    {
      Test::Request req;
      Test::Response res;
      req.input = hello;
      client.call(req, res);
   //   str_msg.data = res.output;
   //   chatter.publish( &str_msg );
   //  nh.spinOnce();
      delay(100);
    }