title: A2DP/SCO -PCM/HCI
body: <p>Wanted to know what exactly is the difference between routing the A2DP/SCO packets through PCM and HCI.</p>
  
  <p>Do both PCM and HCI use ALSA framework for decoding the packets and then send it to speakers ?</p>
  
  <p>Does PCM  require some special hardware and HCI does not ?</p>