title: Pyserial, in_waiting gives empty value '0L'
body: <p>currently I am struggling with serial communication to an external device using Python 2.7/ Pyserial. As an alternative I used a terminal software for data logging: <a href="https://i.stack.imgur.com/tqaer.png" rel="nofollow noreferrer">Screenshot of fomerly used Software</a>.
  One can see the device first gives a header line followed by cyclic updated data strings (separated lines with CR LF each)</p>
  
  <p>Now trying to get the data into Python somehow does not work, cp:</p>
  
  <pre><code>import serial
  ser = serial.Serial('COM8', 38400)
  </code></pre>
  
  <p>Then</p>
  
  <pre><code>ser.inWaiting()
  </code></pre>
  
  <p>gives</p>
  
  <pre><code>0L
  </code></pre>
  
  <p>The buffer seems to be empty when accessing from python while the terminal software runs fine.</p>
  
  <p>I tried setting </p>
  
  <pre><code>ser.setDTR(1)
  ser.dsrdtr=1
  </code></pre>
  
  <p>both without success.</p>
  
  <p>Further information: The device runs on a virtual port splitter. The USB cable is connected to COM3. There are two tools accessing the device using COM6 (for device configuration over HMI) and COM8 for data logging as described here.</p>
  
  <p>I really appreciate any help.</p>
  
  <p>Regards,
  mulm</p>