The master in a piconet whose clock and hopping sequence synchronizes the other devices. Any unit in a piconet can establish a connection to another piconet to form a scatternet. See the figure to the right, which diagrams a scatternet in which piconet A, which consists of four units, is connected to piconet B, consisting of two units. Note that the master unit of A is not the link between the two piconets. As noted earlier, a different hop signal is used for each packet.
Circuit switching can be either asynchronous or synchronous.
As a rule, the answer is no. It is designed to use fast acknowledgement and frequency hopping, which will make connections robust. It is packet-based, and will jump to a new frequency after each packet is received, which not only helps limit interference problems, but also adds to security. This spread spectrum is used to hop from one channel to another, pseudo-randomly, which adds a strong layer of security. Up to 1600 hops per second can be made.