Asynchronous connection-oriented logical transport

- a transmission link used for data communication in the Bluetooth system
- access code(72bit) + packet header(54bit) + payload + CRC(16bit)

- packet types : DM1, DH1, DM3, DH3, DM5, DH5, AUX1

D(1)(2)

  (1) M : rate 2/3 FEC used
      H : no FEC used

  (2) 1 : 1 slot used for one frame
      3 : 3 slots used for one frame
      5 : 5 slots used for one frame