title: Disable AT command on rfcomm connect
body: <p>When connecting to a Bluetooth serial port from Ubuntu:</p>
  <pre><code>adi@Poppy:~$ sudo rfcomm -r connect 0
  Connected /dev/rfcomm0 to 1C:3E:84:FE:4F:69 on channel 8
  Press CTRL-C for hangup
  </code></pre>
  <p>on the client side I receive the following data which is automatically sent from Ubuntu on connect:</p>
  <pre><code>41 54 5e 53 51 50 4f 52 54 3f 0d 41 54 0d 41 54 0d 41 54 0d 7e 00 78 f0 7e 7e 00 78 f0 7e
  
  AT^SQPORT?
  AT
  AT
  AT
  ~
  </code></pre>
  <p>This interferes with what I want to do so I need to prevent Ubuntu from sending any unsolicited data to the client.</p>
  <p>Thanks.</p>