Decoding systems with a decoding engine running on a mobile device with a touch screen

A decoding system, comprising:

• a decoding engine running on a mobile device, the decoding engine in operation decoding signals produced from a read of a buyer's financial transaction card, the decoding engine in operation accepting and initializing incoming signals from the read of the buyer's financial transaction card until the signals reach a steady state, detecting the read of the buyer's financial transaction card once the incoming signals are in the steady state, identifying peaks in the incoming signals and digitizing the identified peaks in the incoming signals into bits;
• a transaction engine running on the mobile device and coupled to the decoding engine, the transaction engine in operation receiving as its input a decoded buyer's financial transaction card information from the decoding engine and serving as an intermediary between a buyer and a merchant, so that the buyer does not have to share his/her financial transaction card information with the merchant;
• and
• wherein the transaction is configured to be coupled to a payment system that provides for establishment of a tab, with a tab being a relationship between the buyer, a payment service and the merchant, with the payment service being a non-affiliate of a buyer's financial institution.