A satellite communications system provides an information channel between remotely located transmitters and receivers. The first end wall has a second coefficient of thermal expansion lower than the first coefficient and has an internal face fastened to a first assembly comprising at least one main plate having a third coefficient of thermal expansion lower than the first coefficient and dimensions in a plane perpendicular to the longitudinal direction less than but substantially equal to those of the cavity. The hot water heater includes a pump that can draw water from any suitable water source, a power source, a heating assembly that quickly and efficiently heats the water as it flows through the heating assembly. Data type aware SGML data definitions facilitate conversion of the data type aware SGML-formatted diagnostics data into a machine format usable by the remote system. An engine controller receives the engine control message and controls a torque andor speed of an engine as a function of the engine control message.