If we hear the large bell ring, we know that it is the one in customer service, so that part is easy.
If the sound is of a small bell coming from the back of the store, we know it is the demo counter, so that part is easy too.
If it is a small bell up front, it is one of the cash register lines. In this case, the person answering goes up to the front, calls out 'two bells', and the person making the request raises his hand.
If the bells sound incoherent, we know that someone's child is just playing with the bell.
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