Interoperability; Device Discovery; Wireless Networks; Piconet - Brainboxes (BL500 Instruction Manual

Interoperability

Device discovery

Wireless networks

Bluetooth PC Card
Interoperability refers to the ability of two devices to communicate with each
other. Now, any Bluetooth device features one or more applications, known as
profiles. For one Bluetooth device to be able to communicate with another, the
two devices must have at least one shared profile. If, for instance, your Bluetooth
device features the profile object exchange, you can exchange business cards
with any other Bluetooth device that has the object exchange profile. Some other
examples of profiles are: file transfer, serial port, and network.
When two or more Bluetooth devices are within range, a link can be established.
However, first of all a Bluetooth device needs to discover the other Bluetooth
devices that are active within its range. This operation is called device discovery.
When another Bluetooth device responds, it supplies necessary information,
some of which concerns its identity: the device name (eg. Adam) or the unique
device address (eg. 00:50:CD:3A:4B:69). A link can now be established to the
discovered device.

Piconet

At the very heart of the Bluetooth technology is the idea of forming small
wireless networks known as piconets. When a Bluetooth device has established a
link to one or more other devices, a piconet has been formed. The device that
initiates a connection acts as the master. The other devices are slaves. The master
controls all traffic in the piconet. Communication between slaves can only take
place via the master. In the below example of a piconet, the laptop (master)
transmits to the handheld computer (slave 1) and the mobile phone (slave 2):

One master, up to 255 slaves

As already mentioned, in a piconet there can only be one master. Furthermore,
up to seven slaves can be active. However, there can be additional slaves which
are not active but remain synchronized to the piconet. Such slaves are referred to
as parked. A parked device can very quickly become active and begin
communicating in the piconet. By swapping active and parked slaves, you can
increase the number of slaves virtually connected to the piconet from seven to
255 devices
Bluetooth Introduction • • • • 4