title: python serial write timeout
body: <p>I have used pyserial for a couple of days. However, a problem occurs today. I met serial write timeout. Several days before, when I used a switch, everything is OK. But today I changed for another switch. Then serial write timeout appears. I did not change any code, but the problem is actually quite severe. More seriously, the timeout not always occurs, which means that sometimes I can write in the serial successfully.</p>
  
  <pre><code>ser = serial.Serial( #Serial COM configuration
      port='COM5',
      baudrate=9600,
      parity=serial.PARITY_NONE,
      stopbits=serial.STOPBITS_ONE,
      bytesize=serial.EIGHTBITS,
      rtscts=True,
      timeout=2,
      writeTimeout=5
    )
  strInput = "show ver"
  ser.flushInput()
  ser.flushOutput()
  ser.write(strInput.encode('utf-8')+b'\n')
  </code></pre>
  
  <p>I have ensured that the port is COM5 and the baudrate of the switch is 9600. Thanks a lot for answering my question.</p>