DS3800HXPC is a CPU Expander Card and is made to work as a CPU board and fits into the GE Speedtronic Mark IV gas turbine control system. The Mark IV system was designed to regulate gas/steam turbines and is capable of controlling all aspects of turbine systems. All four corners are factory drilled, with clips added in two for mounting options. There are 6 resistor network arrays in all. For voltage division or digital to analog conversion, resistor networks can be installed on the board (or vice versa.) On the middle right short edge of the board, there are two male connectors. 218A4637-P2 is the marking on both of these connectors.