A banknote acceptor includes a validator, a removable banknote stacker and a removable non locked banknote cassette. The removable banknote stacker, when secured in the banknote acceptor, is operable by a drive member of the acceptor that remains with the acceptor when the removable banknote stacker is removed. With this arrangement, any operation problems of the removable stacker are easily overcome by replacement of the stacker. Preferably, the banknote acceptor, with the stacker removed, is able to receive and function with a locked banknote cassette having a stacker mechanism internal to the cassette.
