Sony MDR-AS700BT Help Manual page 54

Note
Once BLUETOOTH devices are paired, there is no need for pairing again,
except in the following cases:
Pairing information is deleted after repair, etc.
The headset is paired with 9 or more devices. The headset can be paired with
up to 8 devices; if a new device is paired after 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 headset by the device to be connected is deleted.
The headset is initialized. All pairing information is deleted.
Connecting with a paired iPhone
Copyright 2013 Sony Corporation
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