Sony PCGA-BA1 - Manual (Page 30)

30 GB
Security
Bluetooth wireless communications implement an authentification feature
that can be used to prevent unauthorized access from unidentified Bluetooth
devices. The first time two Bluetooth devices communicate with each other,
a common passkey must be entered before the two devices are allowed to
exchange data. Once a connection has been established, communication
between the devices can proceed for a preset interval (default setting in
BlueSpace software: indefinite), without the need to reenter the passkey.
The Bluetooth USB adapter can be set up so as not to be discovered by
other Bluetooth devices. For information on how to set the device
information storage period and how to set not respond to the device
discovery from remote devices, refer to the help function of the
BlueSpace NE software.