title: plink Unable to open serial port
body: <h2>Configuration:</h2>
  <ul>
  <li>Windows 7</li>
  <li>putty 0.67</li>
  <li>plink 0.67</li>
  </ul>
  <h2>Problem</h2>
  <p>I am trying to use <code>plink</code> to open a serial port connection on COM9.</p>
  <p>Using <a href="http://www.chiark.greenend.org.uk/%7Esgtatham/putty/download.html" rel="nofollow noreferrer"><code>PuTTY</code></a> I can open the serial connection on COM9 and I have a saved session for that serial connection.</p>
  <p>The COM PORT settings are:</p>
  <ul>
  <li>Baud: 115200</li>
  <li>Data: 8-bits</li>
  <li>Stop: 1-bit</li>
  <li>Parity: None</li>
  <li>Flow Control: None</li>
  </ul>
  <p>When I try and use <code>plink</code> instead of <code>PuTTY</code>, I get the following errors:</p>
  <pre><code>$ plink -serial COM9 -sercfg 115200,8,1,N,N
  Unable to open connection:
  Unable to open serial port
  </code></pre>
  <p>But if I use the saved <code>PuTTY</code> session for COM9, it works!</p>
  <pre><code>!plink -load COM9
  help
  help connect    Create connection
  help disconnect Close existing connection
  .
  .
  </code></pre>
  <p>However, I cannot use saved sessions, as my aim is to use <code>plink</code> with <a href="http://expect.sourceforge.net/" rel="nofollow noreferrer">Expect</a> to automate testing with the Device connected by serial, and will be on different machines and different COM ports.</p>