| 摘要 |
In order for a remote embedded application in the form of a vending machine 1 to communicate with a central database 21, a module controller 121 initiates an Internet dial-up session via modem 122, and establishes a link with ISP server 2 (of known IP address), by way of a Telnet session. Communications link 3 having thus been set up, the ISP server 2 establishes an FTP session back to the vending machine module 12, which is set up to operate as an FTP Server. At this point, the ISP server 2 takes control of any necessary exchange of files with the vending machine module 12. Thus, the communication is initiated by the vending machine 1. However, since control of the exchange of files in the FTP session between the database 21 and the vending machine module 12 rests entirely with the ISP server 2, substantially all intelligence and control may remain at the ISP server 2, with the vending machine module 12 having only minimal requirements. |
