WAGO-I/O-SYSTEM 750
Function Description
25
750-921
Bluetooth
®
Adapter
Manual
Version 2.0.1, applicable from FW Version 02
Visibility of the WSA
The device can be configured such that it replies always, never, or only when no
data link exists. The AT command “AT BTSEC INQ” is used for configuring this
setting.
Connectivity of the WSA
The device can be configured such that it accepts a direct link setup by an external
device always, never or only when no radio link currently exists. The AT
command “AT BTSEC PAG” is used for configuring this setting.
A device that is not “visible” for search queries and that can only connect under
certain conditions provides only a very small area of attack to potential attackers.
4.5.2
Encryption
In older versions of the
Bluetooth
®
standard, a so-called
Bluetooth
®
PIN formed
the basis for encryption. Wireless data transfer between the WSA and external
devices is always encrypted. Therefore, a correct PIN must be configured or input
when linking older
Bluetooth
®
devices, regardless of the type of authentication
(see section “Authentication”).
4.5.3
Authentication
The main component of the security mechanism of
Bluetooth
®
technology is
performing mutual authentication before a wireless connection is established. In
principle, you can choose between informal and secure authentication.
•
Bluetooth
®
devices can perform an
informal authentication
without the
need for configuration or user input. This type of authentication offers only
slight security.
•
Secure authentication
on the other hand offers a high degree of security,
but does require user interaction.
Since the WSA has no display or keyboard, all settings related to authentication
must be defined in advance using AT commands. These settings include:
•
Type of authentication. The AT command “AT BTSEC AUTH” is used for
this.
•
PIN for
inbound
links, i.e., links established from external devices to the
WSA. The AT command “AT BTSEC PIN” is used for this.
•
PIN for
outbound
links, i.e., links established from the WSA to external
devices. The AT command “AT CON TAR PIN” is used for this.
•
List of MAC IDs for external devices with which secure authentication is to
be provided. The AT command “AT BTSEC ADEV” is used for this.
Which settings must be made and how is based, among other things, on the
version of the
Bluetooth
®
standard that is supported by the external device and on
the input/output possibilities.