Bluetooth; Specifications; Overview; Piconet - Gestetner B130 Service Manual

4.7 BLUETOOTH

4.7.1 SPECIFICATIONS

Overview

Bluetooth enables radio communication between some portable nodes such as
laptop computers and mobile phones. Some of the advantages are as follows:
• You do not need high-cost equipments.
• Bluetooth supports a lot of protocols for the infrared transmission (IrDA).
• Bluetooth nodes communicate with other Bluetooth nodes with no special
settings.
Standard: Bluetooth 1.1 (Bluetooth Special Interest Group)
Transfer rate: 1 Mbps
Bandwidth: 2.4GHz (Frequency Hopping Spread Spectrum [FHSS])

Piconet

The network of Bluetooth nodes is called Piconet. The nodes communicate in the
ad hoc mode. Piconet consists of eight nodes or less. One of the nodes is the
master; the others are slaves. The master controls the hopping frequencies and
timings. The master also has the registered ID codes of the slaves. The master can
be changed to a slave, and a slave can be changed to the master. When the
master leaves Piconet, one of the slaves becomes the master. Usually, a printer is
a slave of the master.

FHSS (Frequency Hopping Spread Spectrum)

Bluetooth has 79 channels in the
bandwidth from 2,402 MHz to
2,480 MHz. The difference in the
radio frequency between two
adjacent channels is 1 MHz.
Piconet changes the
communication channel 1,600
times in a second. Doing so, the
Piconet networks in the same
LAN can prevent the radio
frequencies from crossing.
SM
CÓPIA NÃO CONTROLADA
Channel
(Radio frequency)
19
CÓPIA NÃO CONTROLADA
BLUETOOTH
Piconet 1
Piconet 2
Piconet 3
Time
B683D903.WMF
B683