The present invention relates to an electronic calculator with the capability of sounding an acoustic alarm capabilities.
In a prior art electronic calculator having a visual display means, there is a substantial probability that the operator may overlook erroneous states such as an overflow or an incorrect key operation while reading account books or sales slips and introducing information via a keyboard. In the case where it takes a considerable amount of time to perform complex calculations, for example, functional calculations, the operator might inadvertently operate a wrong key to render the entire key operations of calculations invalid.
USPTO Backgrounds
USPTO Backgrounds