LG TONE Free TONE-DFP9 Owner's Manual page 18

Plug and Wireless Mode (External Device Connection Mode)
You can connect the charging case to a device such as an airplane stereo
system, treadmill, cassette player, radio, and TV to listen with the earbuds.
1 Push the Plug and Wireless Mode switch on the charging case to
the right to activate the Plug and Wireless Mode. The battery status
indicator flashes in green.
2 Open the cover of the charging case to connect the charging case to
the earbuds. Once the connection is established, the battery status
indicator turns on in green for 3 seconds and turns off.
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