A document management apparatus that communicates with a server and manages confidentiality of electronic data generated by a confidentiality preservation program enables security management on data that is obtained with print screen function. A method is needed to continuously monitor and reliably calculate the fuel’s bulk modulus during engine operation on-board the vehicle, where the fuel’s bulk modulus may be used to infer the ratio of fuels in a fuel mixture or determine the density of supercritical propane when propane is used as the injected fuel. This CO2 lean gas is mixed with clean COG, humidified, and heated in an indirect heater. In this embodiment, the output impedance of a pin on an integrated circuit is automatically matched to the impedance of the load connected to it. The test circuits may be arranged to enable emulation of a termination to be interconnected so as to enable the device to provide a passive link in the data carrying service andor provide throughput testing of the telecommunications line.