Vcoderz Community - Bluetooth !?

Frequently Asked Questions
1.What is Bluetooth?
2.Why the technology is called Bluetooth?
3.How is Bluetooth used?
4.What is the future direction of the Bluetooth standard?
5.How secure is a Bluetooth network?
6.What is Frequency-Hopping Spread Spectrum (FHSS)?
7.Will other RF (Radio Frequency) devices interfere with Bluetooth Devices?
8.Will Bluetooth and Wireless LAN (WLAN) interfere with each other?
9.What is the data throughput speed of a Bluetooth connection?
10.What is the range of Bluetooth transmitter/receivers?
11.What kind of encryption will be used for Bluetooth security?
12.Is Bluetooth practical for use with mobile devices?
13.What is a Personal Area Network (PAN)?
14.What is HomeRF?

Q: What is Bluetooth?
Bluetooth is the name for a short-range radio frequency (RF) technology that operates at 2.4 GHz and is capable of transmitting voice and data. The effective range of Bluetooth devices is 32 feet (10 meters). Bluetooth transfers data at the rate of 1 Mbps, which is from three to eight times the average speed of parallel and serial ports, respectively.

Q: Why is the technology called Bluetooth?
The heart of the Bluetooth brand identity is the name, which refers to the Danish king Harald "Bluetooth" Blaatand who unified Denmark and Norway. In the beginning of the Bluetooth wireless technology era, Bluetooth was aimed at unifying the telecom and computing industries.

Q: How is Bluetooth used?
Bluetooth can be used to wirelessly synchronize and transfer data among devices. Bluetooth can be thought of as a cable replacement technology. Typical uses include automatically synchronizing contact and calendar information among desktop, notebook and palmtop computers without connecting cables. Bluetooth can also be used to access a network or the Internet with a notebook computer by connecting wirelessly to a cellular phone.

Q: What is the future direction of the Bluetooth standard?
At this time, we anticipate the Bluetooth SIG to evolve the Bluetooth technology to provide greater bandwidth and distances, thus increasing the potential platforms and applications used in the emerging personal area networking marketplace

Q: How secure is a Bluetooth network?
Bluetooth is extremely secure in that it employs several layers of data encryption and user authentication measures. Bluetooth devices use a combination of the Personal Identification Number (PIN) and a Bluetooth address to identify other Bluetooth devices. Data encryption (i.e., 128-bit) can be used to further enhance the degree of Bluetooth security. The transmission scheme (FHSS) provides another level of security in itself. Instead of transmitting over one frequency within the 2.4 GHz band, Bluetooth radios use a fast frequency-hopping spread spectrum (FHSS) technique, allowing only synchronized receivers to access the transmitted data.

Q: What is Frequency-Hopping Spread Spectrum (FHSS)?
Frequency-Hopping Spread-Spectrum (FHSS) is a spread spectrum modulation scheme that uses a narrowband carrier that changes frequency in a pattern known to both transmitter and receiver. Properly synchronized, they maintain a single logical channel. To an unintended receiver, FHSS appears as short-duration impulse noise. More simply, the data is broken down into packets and transmitted to the receiver of other devices over numerous "hop frequencies" (79 total) in a pseudo random pattern. Only transmitters and receivers that are synchronized on the same hop frequency pattern will have access to the transmitted data. The transmitter switches hop frequencies 1,600 times per second to assure a high degree of data security.

Q: Will other RF (Radio Frequency) devices interfere with Bluetooth Devices?
No. Bluetooth radios operate on the unlicensed 2.4 GHz (Industrial, Scientific and Medical) frequency band that is shared among other devices (microwave ovens, cordless phones, garage door openers, etc.). Bluetooth radios switch frequencies at such a rapid pace (1,600 times per second) and the data packets are so small that interference from other RF sources is highly unlikely. Bluetooth is a robust communication system.

Q: Will Bluetooth and Wireless LAN (WLAN) interfere with each other?
No, both Bluetooth and WLAN can co-exist. Since Bluetooth devices use Frequency Hopping and most WLANs use Direct Sequence Spreading techniques they each appear as background noise to the other and should not cause any perceivable performance issues.

Q: What is the data throughput speed of a Bluetooth connection?
Bluetooth transfers data at a rate of 721 Kbps, which is from three to eight times the average speed of parallel and serial ports, respectively. This bandwidth is capable of transmitting voice, data, video and still images.

Q: What is the range of Bluetooth transmitter/receivers?
Bluetooth is designed for very low power use, and the transmission range will only be 10m, about 30ft. High-powered Bluetooth devices will enable ranges up to 100m (300ft). Considering the design philosophy behind Bluetooth, even the 10m range is adequate for the purposes Bluetooth is intended for. Later versions of the Bluetooth spec may allow longer ranges.

Q: What kind of encryption will be used for Bluetooth security?
The Bluetooth specification 1.0 describes the link encryption algorithm as a stream cipher using 4 LFSR (linear feedback shift registers). The sum of the width of the LFSRs is 128, and the spec says "the effective key length is selectable between 8 and 128 bits". This arrangement allows Bluetooth to be used in countries with regulations limiting encryption strength, and "facilitate a future upgrade path for the security without the need for a costly redesign of the algorithms and encryption hardware" according to the Bluetooth specification. Key generation and authentication seems to be using the 8-round SAFER+ encryption algorithm. The information available suggests that Bluetooth security will be adequate for most purposes; but users with higher security requirements will need to employ stronger algorithms to ensure the security of their data.

Q: Is Bluetooth practical for use with mobile devices?
Yes. One concern for mobile computing users is power consumption. Bluetooth radios are very low power, drawing as little as 0.3mA in standby mode and 30mA during sustained data transmissions. Bluetooth radios alternate among power-saving modes in which device activity is lowered to maximize the mobile power supply.

Q: What is a Personal Area Network (PAN)?
A Personal Area Network is another name for a Bluetooth Piconet.

Q: What is HomeRF?
HomeRFlike Bluetooth is a specification for connectivity and mobility in a home-like environment. HomeRF Working Group has developed a specification for wireless communications in the home called the Shared Wireless Access Protocol (SWAP).

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