The Singing Machine SML668G Instruction Manual page 9

Connections
Connecting optional wired Microphones:
u
Energy Saving (Auto Power System-APS)
If there is no audio playback, the unit will automatically enter standby mode after 20
minutes. To resume using the unit, press the
APS is designed to save energy.
v
Connect the wired microphone (not included)
into Mic jack u or v (when desired); the
corresponding mic Indicator light will blink.
/ button.
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