title: javax.smarcardio unknown exception 0x1f
body: <p>I'm working on a card reader now. I want to take data from the card. I took uid. I want to take encrypted data. So I want to enter the secure mode and start session. I did something. I send a command apdu to start session but every time return unknown exception 0x1f here is the code.</p>
  
  <pre><code>    TerminalFactory factory = TerminalFactory.getDefault();
  
      List&lt;CardTerminal&gt; terminals = factory.terminals().list();
  
      terminal = terminals.get(0);
      card = terminal.connect("T=1");
      CardChannel channel = card.getBasicChannel();
      byte[] c1 = { (byte) 0x80, (byte) 0x72, (byte) 0x80, (byte) 0x00, (byte) 0x18, (byte) 0x5c, (byte) 0xc5,
              (byte) 0x0a, (byte) 0xa2, (byte) 0x5b, (byte) 0x38, (byte) 0x7f, (byte) 0x81, (byte) 0x3a, (byte) 0x3d,
              (byte) 0x1a, (byte) 0x88, (byte) 0x7d, (byte) 0x26, (byte) 0xfc, (byte) 0x2b, (byte) 0xa8, (byte) 0xa7,
              (byte) 0xdd, (byte) 0xdc, (byte) 0x71, (byte) 0xe0, (byte) 0xf3, (byte) 0xc6 };
  
      ResponseAPDU response = channel.transmit(new CommandAPDU(0xFF, 0x00,0x00,0x00,c1,5,24));
  </code></pre>
  
  <p>This code returns me 6a81( it means function not supported),</p>
  
  <p>if I send directly start session command(84 72 00 00) this time returns unknown exception. </p>
  
  <p>Please help me. You don't have to find the error in code. Tell me How Can I Start Session in a Smart Card. I use HID OMNİKEY 5021 CL.</p>
  
  <pre><code>Exception in thread "main" javax.smartcardio.CardException: sun.security.smartcardio.PCSCException: Unknown error 0x1f
  at sun.security.smartcardio.ChannelImpl.doTransmit(ChannelImpl.java:219)
  at sun.security.smartcardio.ChannelImpl.transmit(ChannelImpl.java:90)
  at CardReader.GetUID.getUID(GetUID.java:48)
  at CardReader.GetUID.main(GetUID.java:86)
  </code></pre>