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(2) Communication procedures for each profile
In Bluetooth communication, there is the possibility of the communication link being cut off by the
radio wave environment. If that happens, run the retry process from the application to re-establish the
link. The retry process must be carried out because it is necessary not just for interference with
wireless LAN and Bluetooth, but also when there is interference with other devices, such as
microwave ovens using the ISM band.
ⅰ Serial profiles
Bluetooth connection can be managed using either the Bluetooth tool or the library, and actual
communication uses the COM port shown in 2.3.
ⅱ DUN (Dial-Up Network)
Bluetooth connection can be managed using either the Bluetooth tool or the library, and actual
communication uses the RAS setting that uses the COM port shown in 2.3. After the connection has
been established, communication via the TCP/IP protocol is possible.
(3) Security
This feature supports security functions regulated in the Bluetooth standard.
Bluetooth security is divided into authentication and encryption. Security is realized by using
PassKey (otherwise known as PIN code).
PassKey is a shared (common) authentication key used when forming a connection and trust
relationship (bonding) between Bluetooth devices. A maximum of 16 characters (in ASCII code) can
be used, but there may be limitations on the no. of digits and usable characters due to the
specifications of partner Bluetooth equipment. Also PassKey input must be completed within 30
seconds from a time when PassKey input request is generated.
Note that PassKey input is not required once “device trust” has been established with Bluetooth
equipment in a previous connection. However, the partner Bluetooth device must also have the trust
relationship in its memory.
Encryption is executed using a link key generated after PassKey exchange and a cipher key
generated from a 128-bit random number. Here, the partner Bluetooth equipment also must support
the encryption. PassKey exchange is required for Bluetooth connection when encryption is set
enabled.
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