Every Bluetooth device has a globally unique 48-bit address. This address is utilized in piconet identification, packet header error checking, authentication, and encryption.

Audio, particularly voice, is specially handled separate from data using baseband packets called Synchronous Connection-Oriented (SCO) packets. Audio takes place at 64 Kbps using either Pulse Code Modulation (PCM) or Continuous Variable Slope Delta (CVSD) modulation.

In the "Interactive Conference" Bluetooth usage model, business cards and documents can be exchanged and shared among participants at a meeting or conference.

The Bluetooth transceiver is a frequency-hopping spread spectrum (FHSS) radio system operating over (typically 79) 1 Mhz-wide channels. Bluetooth wireless technology operates in the 2.4 GHz ISM band.

The Bluetooth modulation technique is Gaussian Frequency Shift Keying (GFSK) with a BT-product of 0.5. Frequency Shift Keying (FSK) uses two closely spaced frequencies to represent 0's and 1's. GFSK employs a Gaussian filter to more efficiently fit into a smaller frequency band.

In the "Ultimate Headset" Bluetooth usage model, a wireless headset gives you hands-free access to a mobile telephone, wired phone, and computer workstation in the office or on the road.

In the "Internet Bridge" Bluetooth usage model, you can use your laptop to access the Internet wherever you are. On the road your laptop can connect using your cell phone while inside the office you can be connected to a high-speed LAN through a data access point - without any cables or wires.

A standard developed by the Infrared Data Association (IrDA) and part of the Bluetooth wireless technology, infrared mobile communications (IrMC) defines a method for data objects like electronic business cards, e-mail, and calendar entries to be synchronized (updated) between mobile devices.

The industrial, scientific, medical (ISM) bands are set aside by the Federal Communications Commission for unlicensed use. The Bluetooth radio specification uses the 2.4 GHz ISM band. The IEEE 802.11 (1 and 2 Mbps wireless LANs) standard also uses this same frequency band.

When devices establish a Bluetooth link, one serves as master and the other devices are slaves. A master device has no special privileges and only governs the synchronization of the communication between the devices. A master device can communicate with up to 7 active slaves and up to 255 parked slaves.

A standard developed by the Infrared Data Association (IrDA) and part of the Bluetooth specification, the object exchange (OBEX) protocol is essentially a binary HTTP protocol optimized for ad-hoc wireless links and useful for exchanging electronic business cards (vCard), schedule entries (vCalendar), e-mail (vMessage), notes (vNote), and other data.

A slave device on a Bluetooth network or piconet can be in either an active or park state. There are only 7 active slave devices allowable on a piconet at any given time. However, there can be up to 255 parked slave devices. Parked devices retain time synchronization with the piconet but are otherwise disconnected and use the lowest power.

In the "Three-in-one Phone" Bluetooth usage model, a single phone can serve as a mobile phone, a cordless phone used with a base station, and a "walkie-talkie" for phone-to-phone communications with another phone in the local vicinity.

A Bluetooth network or piconet is made up of a master device and up to 7 active slaves. In addition, up to 255 parked slave devices can be placed in an active state as needed as long as there are no more than 7 active slaves at any time. When two or more piconets overlap in time and space, they become a scatternet where the slave device can have multiple connections.

In writing the Bluetooth technical specification, a number of usage models or profiles were created as an integral part of the marketing objectives that the specification was intended to address. These Bluetooth profiles provide examples of applications that the technology makes possible.

RFCOMM is a layer in the Bluetooth protocol stack. It facilitates the use of serial communication over Bluetooth wireless links. In this way legacy serial port-based applications can be used. RFCOMM is modeled after ETSI TS 07.10, a European telecommunications standard.

The Bluetooth Service Discovery Protocol (SDP) defines a standard method for Bluetooth devices to discover and learn about services offered by other Bluetooth devices. It also specifies how a device describes a service. SDP is based on Motorola's Piano(tm) platform for wireless products.

Bluetooth wireless technology includes device authentication and link encryption of data. Device authentication uses a challenge-response transaction. Link encryption uses an encryption key whose key size is negotiated (up to 128 bits). Device authentication is mandatory for all Bluetooth devices. Link encryption is optional.

In the "Automatic Synchronizer" Bluetooth usage model, as soon as you enter the office, the address list and calendar on your desktop computer are automatically updated to agree with the information in your notebook computer and/or Personal Digital Assistant, and vice-versa.

Although existing modem AT commands can be used over the RFCOMM protocol layer to accomplish some types of telephony control (dialing, hang-up, fax, etc.), a separate telephony protocol layer TCS-BIN is also defined to support call control, group phone conference, call forwarding, multiple extensions, and connectionless ("walkie-talkie") features.

Bluetooth™ is named for a 10th century Viking king, Harrald Blåtand (Bluetooth) who united Denmark and Norway and brought Christianity to Scandinavia during his reign. The name for this open standard was chosen because the technology originated in Scandinavia (by Ericsson) and is intended to unify the telecom and computing industries.

Bluetooth wireless technology is an open, global standard for using small, affordable radio links to provide cable-free connections, communication, and networking between PCs, mobile phones, and other devices.

Bluetooth Revealed
by Brent A. Miller, Chatschik Bisdikian

An excellent starting point for anyone who wants to know what Bluetooth is about, application scenarios, and the standards behind Bluetooth. If you're intending to learn about, build, deploy, or market Bluetooth products, this is the place to start.

Buy this book now (save 15%) and we donate WKMN's proceeds to the Second Harvest Food Bank and Ecumenical Hunger Program.