Embossed card reader

Abstract

A low cost, compact embossed card reader for reading embossed characters on credit or debit cards and for integration into a combined magnetic character/magnetic stripe terminal. A low-profile housing forms a card path and provides a surface for mounting a removable read head. The housing includes an integrated card guide for guiding the embossed characters along a linear path adjacent the read head. The read head includes a plurality of pins mounted orthogonally to the card, and aligned so as to scan each of the embossed characters in parallel paths as the card moves relative to the read head. The pins move upwardly as they encounter an embossed character and open a normally closed switch formed by a printed circuit board and a plurality of leaf spring fingers. Improved data acquisition and decode methods for sampling the embossed character data and decoding the data to form an account number. The data acquisition method samples the embossed characters at a predetermined rate. The transitions in the data from any of the pins are detected and the raw data is stored. The raw data is filtered or debounced and remaining invalid states are deleted. The remaining data states are used to decode the characters on the card. A first valid state determines whether a second data window is a valid second expected value state. If an expected second value state does not follow a first value state, the method attempts to decode the character backward from its trailing edge.