title: Write to Cisco Switch with c# System.IO.Ports.SerialPort doesn't always work
body: <p>i wrote a simple code in <code>c#</code> <code>using System.IO.Ports.SerialPort</code> that opens a serialport connection to a Cisco switch and writes to it. </p>
  
  <p>it works fine but only if i open the connection via <code>putty.exe</code> first and then close putty, and run my code.</p>
  
  <p>then my code works fine for a day WITHOUT PUTTY(writes successfully to the switch)  but tomorrow when i try my code again it doesn't work unless i open putty again and connect to the switch the same way.</p>
  
  <p>any ideas why this happens? 
  the switch is Cisco Switch 2960cx.</p>
  
  <p>thank you</p>