Abstract: The present invention includes transaction processing systems that process transactions from merchant systems designed to convert the presentation of a transponder device into electronic debits from a checking account. The transaction processing systems also can provide risk assessment, validation or user data and/or MICR data, and/or transaction guarantee services.

Abstract: The present invention includes a merchant computing system that recognizes a wireless device, such as, for example, a wireless transponder, and converts the presentation of the wireless device into transaction requests for electronic debits to a checking account. The merchant computing system-enrolls users who provide MICR data identifying their checking account, and whose risk assessment falls within predetermined enrollment parameters. Moreover, the merchant computing system accepts those transactions which also fall within predetermined transaction parameters.