The ECU-C is the APsystems commercial energy communication unit, serving as the information gateway for APsystems microinverters. It collects module-level performance data over a ZigBee 2.4 GHz link and makes it available through the APsystems EMA monitoring platform. A single ECU-C can communicate with a maximum of 100 microinverters, though the actual count depends on array size, distance and physical obstructions.

Connectivity includes 10/100M auto-sensing Ethernet, integrated 802.11g/n Wi-Fi, RS232, RS485, RJ45 and USB. Two external SMA-type antennas serve the ZigBee and Wi-Fi radios. Input power is 110-277 VAC, 50/60 Hz, single or three phase, or 12-16 VDC, with 3 W consumption.

Beyond monitoring, the ECU-C provides PV production metering through current transformers at approximately 0.5 percent accuracy, with optional consumption monitoring at approximately 2.5 percent. It also supports limited and zero power-export functions, using an internal relay to control an external device based on measured exported power. The unit measures 8.3" x 4.7" x 1.6", weighs 1.1 lb, and is rated for -40°C to 65°C operation. Standard warranty is 3 years.