Abstract: A lightning direction finder controller (LDFC) for use at remote sites in a Lightning Detection Network provides information on lightning return strokes to a network controller. The LDFC digitizes and processes return stroke data from an analogue direction finder unit, time tags each return stroke with an absolute time accurate to the nearest 10.sup.-4 second of NIST time, and provides an interface for satellite and/or land line communication of lightning flash data to the network controller. The LDFC includes a CPU board, a multi-function analogue and digital input/output board that provides an interface to the analog direction finder unit, and an Interface Facility that provides an interface for: satellite and/or bisynchronous communications, a local data storage device, diagnostic devices, and a satellite controlled clock. A watchdog timer on the Interface Facility resets the CPU of the LDFC when data communications cease, or the execution of the main program halts.