text: #!/usr/bin/env python
  
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  __author__ = "mferguson@willowgarage.com (Michael Ferguson)"
  
  import rospy
  from rosserial_python import SerialClient, RosSerialServer
  from serial import SerialException
  from time import sleep
  import multiprocessing
  
  import sys
  
  if __name__=="__main__":
  
      rospy.init_node("serial_node",anonymous=True)
      rospy.loginfo("ROS Serial Python Node")
  
      port_name = rospy.get_param('~port','/dev/ttyUSB0')
      baud = int(rospy.get_param('~baud','57600'))
  
      # for systems where pyserial yields errors in the fcntl.ioctl(self.fd, TIOCMBIS, \
      # TIOCM_DTR_str) line, which causes an IOError, when using simulated port
      fix_pyserial_for_test = rospy.get_param('~fix_pyserial_for_test', False)
  
      # TODO: should these really be global?
      tcp_portnum = int(rospy.get_param('/rosserial_embeddedlinux/tcp_port', '11411'))
      fork_server = rospy.get_param('/rosserial_embeddedlinux/fork_server', False)
  
      # TODO: do we really want command line params in addition to parameter server params?
      sys.argv = rospy.myargv(argv=sys.argv)
      if len(sys.argv) >= 2 :
          port_name  = sys.argv[1]
      if len(sys.argv) == 3 :
          tcp_portnum = int(sys.argv[2])
  
      if port_name == "tcp" :
          server = RosSerialServer(tcp_portnum, fork_server)
          rospy.loginfo("Waiting for socket connections on port %d" % tcp_portnum)
          try:
              server.listen()
          except KeyboardInterrupt:
              rospy.loginfo("got keyboard interrupt")
          finally:
              rospy.loginfo("Shutting down")
              for process in multiprocessing.active_children():
                  rospy.loginfo("Shutting down process %r", process)
                  process.terminate()
                  process.join()
              rospy.loginfo("All done")
  
      else :          # Use serial port
          while not rospy.is_shutdown():
              rospy.loginfo("Connecting to %s at %d baud" % (port_name,baud) )
              try:
                  client = SerialClient(port_name, baud, fix_pyserial_for_test=fix_pyserial_for_test)
                  client.run()
              except KeyboardInterrupt:
                  break
              except SerialException:
                  sleep(1.0)
                  continue
              except OSError:
                  sleep(1.0)
                  continue
  
  