Bluetooth uses a radio technology called frequency hopping spread spectrum data being sent and transmits chunks of it on the 79 band (1 MHz each, centered MHz 2480 to 2402) has the chops in the range from 2400 to 2483.5 (MHz allowing guard band). The range globally unlicensed Industrial, Scientific and Medical (ISM) short range radio frequency band at 2.4 GHz.
Essentially Gaussian frequency shift keying modulation (GFSK) modulation available only plan, then, Bluetooth + 2.0 EDR, π/4-DQPSK and 8DPSK since the introduction of modulation can be used between compatible devices. Devices GFSK with functioning basic rate (BR) mode can be activated in the 1 Mbit / s is the instantaneous data rate is possible. Term Enhanced Data Rate (EDR) π/4-DPSK and 8DPSK plans, each 2 and 3 Mbit / s respectively, is described to. Bluetooth radio technology in the (BR and EDR) mode combining a “BR / EDR radio” is classified as.
Bluetooth is a master – slave structure is a packet-based protocol. Seven slaves in a piconet with a master can communicate, all devices share the master clock. Packet exchange basic clock, the master, which is based on 312.5 μs intervals defined by the ticks. A slot of two clock ticks 625 μs, 1250 μs for the two slots have a slot pair. Single-slot packet, the master transmits in the slot and received in odd slots in simple terms, slave, by contrast, is in the slot and transmits in odd slots. Packet 1, 3 or 5 slots may be long but in all cases, the master transmits in even slots and slaves will transmit in odd slots.
Bluetooth to connect and fax, mobile phones, telephones, laptops, personal computers, printers, Global Positioning System (GPS) receivers, digital cameras, and exchange information between devices such as video game consoles – to provide a secure way to provide does.
Communication and connection
Seven devices in a piconet a master Bluetooth device (an ad hoc computer network using Bluetooth technology), not all devices communicate with a maximum of the range can support. Devices to switch roles, agreement can and can become a slave master (for example, a headset to a phone to the master started as a connection to the connection initiator As, however, may prefer to be the slave).
For the connection of two or more piconets Bluetooth core specification provides some tools to form a scatternet with a slave in a piconet and the other role plays.
At any time, data master and another device (except for a used transmission mode) can be transferred between. Chooses to master the slave device, typically, a device to another switch in a fast round-robin fashion. Since the master know which slave, a slave (in theory) get a slot in each of the listener, being a master to a slave’s load is lighter than selects. Being a master of slaves is seven, plus a Master’s tough being a slave. Scatternets specification as required in practice is unclear.
Many USB Bluetooth adapters or “dongles” are available, some of which also include an IrDA adapter. Older (pre-2003) Bluetooth dongles, however, has limited capabilities, only the Bluetooth Enumerator and a less powerful Bluetooth radios offer incarnation. Such computer devices with Bluetooth link with a distance of 100 meters, but they could not offer as many services as the modern adapters.
