This unit checks the polarities of loudspeaker units and open voice-coil for tweeters of the speaker system.
The result of a check is shown with a green(GO) or red(NG) LED indicator within approximately 0.2seconds.
An external signal can be inputted when the selector switch is set so.
Polarity: +(green) -(red)
Tweeter Open: GO(green) NG(red)
Polarity Checking Microphone: AP-1291(Accessory)