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A device equipped with Bluetooth technology can send and receive data within the frequency range (802.15.1) of
2.4GHz ISM (Industry Scienti c and Medical) by communicating wirelessly with radio frequency in FHSS (frequency-
hopping spread spectrum). Bluetooth wireless technology is, in particular, designed for short-range communication (10
m / 30 ft) and low-power consumption.
CW20, equipped with Bluetooth technology, is able to exchange information (e.g. les, appointments, tasks) with other
Bluetooth-support devices such as phones, printers, access points, or other mobile computers. To use CW20 as a
modem, you can establish a dial-up modem connection between a computer and CW20.
AFH (Adaptive Frequency Hopping), a way of avoiding xed frequency interference, can be applied to Bluetooth voice.
In order for AFH to operate correctly, all devices of piconet (Bluetooth network) must support AFH. When searching
and connecting to devices, AFH is not used. Refrain from using Bluetooth pairing or search when an important
802.11b communication is underway. The AFH for Bluetooth consists of four major components:
It is a way of detecting interference according to the pre-de ned channel masks or standards of each channel.
Link management– It distributes adjusted AFH information over the rest of Bluetooth network
Modi cation of hopping order– It prevents interference by selectively reducing the number of hopping channels.
Channel maintenance –It is a way of re-evaluating channels periodically.
When AFH is activated, Bluetooth communication hops to near high-speed 802.11b channels instead of passing
through them.
Bluetooth wireless connection of CW20 is working at Class 2 device power level. The maximum output power is 2.5
mW and the estimated distance is 10 m (32.8 ft). The distance depending on power levels may differ in the measured
environments such as open space or closed of ce space, etc. Therefore, it is dif cult to de ne the right distance due
to the differences in power and devices.
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