Abstract: A POS (point-of-sale) Check Service converts any paper check online and in real-time into an electronic funds transaction. The paper check is returned to the customer. A merchant enters the amount of the sale and electronically captures checking account data from the MICR line encoded on the check. The check data, identification data and sale amount are forwarded to a service organization for processing. The service has three options: Conversion Only; Verification with Conversion; and Guarantee with Conversion. Under Conversion Only the transaction is approved or declined with no account verification processing and the merchant retain the risk of loss. Under Verification with Conversion the check authorization message is routed to the participating drawee bank or to a third-party authorizing agent for verification that the check will be paid. Under Guarantee with Conversion, the check authorization request message is routed to the participating drawee bank or to a third party to guarantee the check.