Appendix A Hardware Pass-through Connection In a pass-through connection, it is possible to control the customer display, printer, and cash drawer from one computer serial port, via the DP-501. In the pass-through connection via the DP-501, data flows as indicated below. DP-501 Computer DM-D500 (Display) Transmit data from the computer Printer Transmit data from the printer to the computer Power supply Transmit data to the printer • In the pass-through connection, data from the computer is first stored in the receive buffer of the display, and then processed sequentially to only send data for the printer to the printer.
Data from the printer is sent directly to the computer, without passing through the display. • Data for the customer display and that for the printer are distinguished by the select peripheral device com- mand. • Settings for communication must be the same for all of the computer, printer, and customer display. 63