Bluetooth defines several frame formats, the most important of which is
shown in two forms in Fig. 4-36. It begins with an access code that usually identifies the master so that slaves within radio range of two masters can tell which traffic is for them. Next comes a 54-bit header containing typical MAC sublayer
fields. If the frame is sent at the basic rate, the data field comes next. It has up to
2744 bits for a five-slot transmission. For a single time slot, the format is the
same except that the data field is 240 bits.