User Manual

Wireless
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band (802.15.1). Bluetooth wireless technology is specifically designed for short-range (10 meters (32.8 feet))
communication and low power consumption.
Devices with Bluetooth capabilities can exchange information (e.g., files, appointments, and tasks) with other
Bluetooth enabled devices such as printers, access points, and other mobile devices.
Adaptive Frequency Hopping
Adaptive Frequency Hopping (AFH) is a method of avoiding fixed frequency interferers, and can be used with
Bluetooth voice. All devices in the Bluetooth network (piconet) must be AFH-capable in order for AFH to work.
There is no AFH when connecting and discovering devices. Avoid making Bluetooth connections and
discoveries during critical 802.11b and other 2.4G WLAN
communications. AFH for Bluetooth consists of four
main sections:
• Channel Classification - A method of detecting an interference on a channel-by-channel basis, or
pre-defined channel mask.
• Link Management - Coordinates and distributes the AFH information to the rest of the Bluetooth network.
• Hop Sequence Modification - Avoids interference by selectively reducing number of hopping channels.
• Channel Maintenance - A method for periodically re-evaluating the channels.
When AFH is enabled, the Bluetooth radio “hops around” (instead of through) the 802.11b and other 2.4G
WLAN high-rate channels. AFH coexistence allows Enterprise devices to operate in any infrastructure.
The Bluetooth radio in this device operates as a Class 1 device power class. The maximum output power is
9mW and the expected range is 10 meters (32.8 ft.). A definition of ranges based on power class is difficult to
obtain due to power and device differences, and whether one measures open space or closed office space.
NOTE: Use of Bluetooth wireless technology is not recommended when high rate 802.11b operation using 2.4G channel is
required.
Security
The current Bluetooth specification defines security at the link level. Application-level security is not specified.
This allows application developers to define security mechanisms tailored to their specific need. Link-level
security occurs between devices, not users, while application-level security can be implemented on a per-user
basis. The Bluetooth specification defines security algorithms and procedures required to authenticate
devices, and if needed, encrypt the data flowing on the link between the devices. Device authentication is a
mandatory feature of Bluetooth while link encryption is optional.
Pairing of Bluetooth devices is accomplished by creating an initialization key used to authenticate the devices
and create a link key for them. Entering a common personal identification number (PIN) in the devices being
paired generates the initialization key. The PIN is never sent over the air. By default, the Bluetooth stack
responds with no key when a key is requested (it is up to user to respond to the key request event).
Authentication of Bluetooth devices is based-upon a challenge-response transaction. Bluetooth allows for a
PIN or passkey used to create other 128-bit keys used for security and encryption. The encryption key is
derived from the link key used to authenticate the pairing devices. Also worthy of note is the limited range and
fast frequency hopping of the Bluetooth radios that makes long-distance eavesdropping difficult.
Recommendations are:
• Perform pairing in a secure environment
• Keep PIN codes private and do not store the PIN codes in the device
• Implement application-level security.