| 摘要 |
A system that includes a first input/output (I/O) device configured to generate a code based at least in part on a unique machine identifier of the first I/O device, and a second I/O device communicatively coupled to the first I/O device via a network. The second I/O device is configured to read the code from a tangible medium, parse the code to determine the machine identifier, transmit a validation request directly to the first I/O device via the network, and receive a response message directly from the first I/O device, wherein the response message indicates a number of credits available to a user at the second I/O device. |
