Pantech C520 User Manual page 24

Retrieving Call in Headset/Handsfree/Phone
This function becomes available when Bluetooth Headset/Handsfree are
connected during a call. To talk using the Bluetooth Headset/Handsfree
during a phone, select [Option] -> [Retrieve Headset] or [Retrieve
Handsfree]. On the other hand, selecting . [Option] -> [Retrieve Phone]
allows you to talk using the phone again.
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