A light-emitting diode (LED) luminaire comprises an emergency-operated portion comprising a rechargeable battery with a terminal voltage, a self-diagnostic circuit, and a node modulator-demodulator (MODEM). The LED luminaire can auto-switch from a normal power to an emergency power according to availability of the normal power and whether a rechargeable battery test is initiated. The self-diagnostic circuit comprises a clock and is configured to initiate self-diagnostic tests and to auto-evaluate battery performance according to test schedules with the terminal voltage examined and each of test results sent to a remote control unit that comprises a data-centric circuitry comprising a variety of data communication devices configured to initiate command data with phase-shift keying (PSK) signals transmitted via a principal MODEM and to periodically collect each of test data to and from the node MODEM. The test data assembled are ultimately transferred to a root server for further reviews.