are preferably implemented when pots is not available pprf is not desired or practical and cellular coverage is assured as with a pots implementation an rfu can directly dial into the internet intranet via an isp this is the next mostly costly alternative due to the monthly charges of cellular airtime finally wireless rf satellite interfaces can be used any time the previous telemetry options are not available this option represents the greatest cost to the customer due to the costs of satellite bandwidth usage the tamper function is incorporated into the rfu and provides alarm notification that the system is being tampered with or that diagnostics have failed this is an output only function that provides its status word to the control function the gps function serves two purposes 1 provide a very precise lt 10e u2212 5 second resolution time stamp to the data and 2 if the rfu is installed on a mobile platform provide extremely accurate global positioning information for incorporation into the status word the former is used to specifically time correlate multiple rfu data sets at the network operations center with the latter can be used by rfus that are mobile in design such as autonomous underwater vehicles the power system can be driven from standard electrical or battery power where delivery and maintenance of such power is economically feasible alternatively power can be generated at or near an rfu through a variety of alternative energy means including but not limited to solar power hydrodynamic power or windmills the latter.