A REX activation detection and control module system configured to allow a REX device having at least four connectors to electrically connect with ACS devices having at least four connectors, while only connecting two wires to the REX device. The system comprises a first REX input/output device comprising two couplings and a second REX input/output device comprising at least four couplings. The system also comprises a current sense amplifier electrically connected to the first REX input/output device, the current sense amplifier configured to measure current from either the first REX input/output device. The system also comprises a microcontroller electrically connected to the current sense amplifier, the microcontroller configured to monitor the rolling average of the measured current output from the current sense amplifier. When the microcontroller detects an anomaly within the rolling average of the measured current, the microcontroller will activate the relay.