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Ushing the button while sewing immediately reverses sewing, and pushing the button A once stops the needle-up, and pushing twice does the needle-down. So, there is no reason to manipulate the pulley. In case where backtack is required during sewing, backtack is carried out by stopping the machine and touching the button B once. With respect to thread trimming after backtack, pushing the button B once and trimming carries out trimming without backtack.