Sony SRS-BTS50 - Manual (Page 57)

Once BLUETOOTH devices are paired, there is no need for pairing again,
except in the following cases:
Pairing information has been deleted after repair, etc.
The system has been paired with 9 or more devices. The system can be
paired with up to 8 devices; if a new device is paired after the first 8 devices
have been paired, the device whose latest connection time is the oldest among
the 8 paired devices is replaced by the new one.
When recognition of the system by the device to be connected has been
deleted.
When the system is initialized, pairing information is deleted.
Copyright 2013 Sony Corporation
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