Enable real-time public safety passive DAS antenna and transmission line monitoring with Microlab’s Smart Coupler. Specialized directional couplers with embedded IoT circuitry are powered and communicate with a headend gateway unit over the coaxial cabling. The gateway enables diagnostics and communications to and from each SmartCoupler throughout a building. Unlike cellular distributed antenna systems (DAS), conventional two-way, push-to-talk, public safety radio DAS does not have constant network traffic. Critical communication systems carry radio traffic only during an incident. Through a graphical user interface, system integrators, authorities with jurisdiction, or building owners may connect to the gateway locally or via the internet to continuously monitor the in-building, emergency first responder DAS network’s integrity. The output of a building’s 130 – 960 MHz RF signal source passes through the gateway and connects to the DAS. Original signal integrity is maintained and combined with SmartCoupler’s IoT diagnostics and communication. The SmartCoupler replaces the required tappers and couplers that are typical in a passive DAS.