Silent trade

Silent trade, also called silent barter, dumb barter ("dumb" here used in its old meaning of "mute"), or depot trade, is a method by which traders who cannot speak each other's language can trade without talking. Group A would leave trade goods in a prominent position and signal, by gong, fire, or drum for example, that they had left goods. Group B would then arrive at the spot, examine the goods and deposit their trade goods or money that they wanted to exchange and withdraw. Group A would then return and either accept the trade by taking the goods from Group B or withdraw again leaving Group B to add to or change out items to create an equal value. The trade ends when Group A accepts Group B's offer and removes the offered goods leaving Group B to remove the original goods.