Sony SGPT11 - Manual (Page 21)

About Bluetooth(R) Security
Bluetooth wireless technology has an authentication function that allows you to determine with whom you choose to communicate.
With the authentication function, you can prevent any anonymous Bluetooth devices from accessing your tablet device. The first time
two Bluetooth devices communicate, a common passkey (a password required for authentication) should be determined for both
devices to be registered. Once a device is registered, there is no need to re-enter the passkey.
Your tablet device will be detected by other Bluetooth devices, only when it is set to allow detection by other Bluetooth devices. You
can set the time to accept the detection, or whether or not to allow reception after both devices are connected.