Ezurio has pushed the boundaries of Bluetooth with a module that gives the short-range wireless protocol a range of 1km.

Despite the headline-grabbing claim, the range may not be the main selling point of the BISM II PA, a postage-stamp sized circuit board which can be built into hand-held devices. It is available immediately, with volume production in three months.

"There are customers who may wish to exploit the full potential of the range provided by this new range of modules," said John Keates, head of product marketing at Ezurio. In fact the relatively high power (700mW) and on-board antenna of the device will most often find ensuring a Bluetooth connection over a shorter range, in changing or busy environments, he said: "The particular strengths of this module are with the low connection 'hysterisis' and its ability to cope with demanding environments."

"It has long been a cause of frustration that so many commentators and engineers have assumed that Bluetooth is just a short range technology", said Nick Hunn, chief technical officer of Ezurio. It's most often seen in headsets, but the standard has always had a high-power option with a range greater than 100m, and Ezurio has already supplied "hundreds of thousands" of Bluetooth modules to customers using the protocol over these distances.

The most obvious and commercially important of these applications are credit card readers, which allow staff in large shops and restaurants to serve customers anywhere on the premises, and where a high-power connection would increase reliability.

"Five million secure financial transactions are handled by Bluetooth every day," said Hunn. In shops and factories, the radio environment may change rapidly, causing a weaker module to lose its connection.

The module supports Bluetooth version 2.0 and includes a full firmware protocol stack.

The Wi-Fi community will also be looking closely at this development. If high power Bluetooth becomes widespread, it might affect the availability of bandwidth in the 2.4GHz spectrum that is used by both Wi-Fi and Bluetooth. IT shouldn't be a problem, says Keates, as the Ezurio module gains its range more by sensitive electronics and filters than high power, and the Bluetooth protocol is agile, moving quickly to unoccupied parts of the spectrum. In any case, Wi-Fi will eventually move to the new 802.11n standard and shift to the 5GHz band.