Secure front-end interface

Abstract

A secure front-end interface for a PLC, RTU or similar device is disclosed. A first server is coupled to the PLC via a communications link and is configured to receive status information from the device and transmit the information to a second server via a one-way data link. The second server has a network interface for coupling to a network and receives the information from the first server via the one-way data link and outputs the information via the network interface based upon a user request. The front-end interface may further include a second one-way data link coupled from the second server to the first server to allow user command entry. The secure front-end interface may alternatively consist only of a single server coupled between the device and the network which requires a user to enter a password before obtaining access to the status information.

Dependencies are inferred from the claim text.