The baseband also manages asynchronous and synchronous links, handles packets and does paging and inquiry to access and inquire Bluetooth devices in the area. Physical Channe l Bluetooth operates in the 2.4 GHz ISM band . The channel is represented by a pseudo-random hopping sequence hopping through the 79 or 23 RF channels. Two or more Bluetooth devices using the same channel form a piconet . The channel is divided into time slots where each slot corresponds to an RF hop frequency.
Consecutive hops correspond to different RF hop frequencies.
The time slots are numbered according to the Bluetooth clock of the piconet master. A TDD scheme is used where master and slave alternatively transmit. The packet start shall be aligned with the slot start. The SCO link mainly carries voice information. The master can support up to three simultaneous SCO links while slaves can support two or three SCO links.