Technologies - Bluetooth

Just cable replacement or even more?

In the early days of Bluetooth technology development (made available to public in 1998), Bluetooth soon achieved its reputation as a wireless cable replacement technology. The so called RFCOMM protocol, which is part of the Bluetooth Core Specification (www.bluetooth.org) describes a complete simulation of a legacy wired serial port connection over the air.

But Bluetooth technology is far from being only a cable replacement. It can connect one master at the same time with seven slaves forming a so called piconet, and the slaves themselves can be a master to a different piconet, thus forming a so called scatternet. Apart from its capability of transferring asynchronous data at a maximum speed of 721 kb/s (referring to Bluetooth specification version 1.2, the Enhanced Data Rate (EDR) specification in version 2.0 even allows data rates up to 3 Mb/s), Bluetooth technology also provides 3 synchronous channels at a data rate of 64 kb/s each.

When Bluetooth technology finally got the market breakthrough in 2002, the Bluetooth chipset quantity was 10 million units per year worldwide, mainly due to the fact that leading mobile phone manufactures delivered their products in large quantities with Bluetooth technology on board. By 2004 the quantity had increased rapidly to 115 million units per year worldwide and is still growing.

Bluetooth technology is extremely versatile for different uses due to its Profile based nature. Starting with profiles like Serial Port Profile, Dial-up Networking Profile or Object Push Profiles in the early days, the actual Bluetooth specification now comprises more than 25 Profiles describing how to transfer asynchronous or synchronous data in different scenarios.

Working in the 2.4 GHz ISM band, Bluetooth devices have a range of 10 – 100m, depending on the specific power class of the device. Bluetooth has built in error correction, offers good security (authentication and encryption) and is very robust due to its frequency hopping system. Relatively low power consumption (typically 30mA) and a small footprint are two more features, which make Bluetooth technology very attractive for many wireless appliances.

SND offers a complete and certified version 1.2 upper layer Bluetooth stack comprising L2CAP, RFCOMM and SDP on the protocol side and Serial Port Profile (SPP), Generic Access Profile (GAP) and Service Discovery Application Profile (SDAP) on the protocol side. The Bluetooth protocol stack is based on SND’S operating system HyNetOS.

To learn more about Smart Network Devices Bluetooth Products please download Bluetooth Brochure and Micro BlueTarget Kit.