Bluetooth and OBEX - Beginning J2ME: From Novice to Professional - page 196

The Bluetooth Service Model
Figure 12-3 illustrates typical interactions between Bluetooth devices.
Figure 12-3. Bluetooth device interactions
In Figure 12-3, note that a single Bluetooth device can be offering multiple services at the
same time. Bluetooth devices can also support both client and server functionality simulta-
neously. On a hardware level, a single master Bluetooth device can synchronize up to seven
slave devices in a Bluetooth piconet.
Devices are the discoverable entities in a Bluetooth network. The discovery process is
called an inquiry in Bluetooth lingo. You need to perform an inquiry to discover devices in your
PAN before finding out what services the devices are offering.
Each service in a Bluetooth network is uniquely identified by a UUID. Any particular
device in the Bluetooth network can be offering zero or more services. The same service may
be offered by more than one device in the network. For example, one can easily imagine a
printing service offered by a number of printers in the same room.