Patent ID: 8534546

Claim:
A system, comprising: a merchant's mobile device configured to be coupled to a card reader output jack insertable and removable from a microphone port of the mobile device; a decoding engine configured to decode signals from a swipe of a card through a slot of the card reader; a filter that smooth's out at least a portion of high frequency noise of signals received from the card reader; a user interaction engine which in operation, accepts an input of information of a buyer's financial transaction with a merchant; a transaction engine taking as its input decoded card information from the decoding engine and a transaction amount from the user interaction engine, the transaction engine serving as an intermediary between the buyer and the merchant, so that the buyer's card information is not stored with the merchant's mobile device, the transaction engine accepting information of the buyer's financial transaction and the buyer's card information; communicates with a third party financial institution to authorize the transaction, the third party financial institution being coupled to a buyer's financial institution that issued the card; the third party financial institution presenting results of the transaction to the buyer without sharing the card information with the merchant's mobile device; and a transaction database in communication with the transaction engine and is external to merchant's mobile device and configured to send a receipt to the buyer.