This extension main unit is designed to connect with the HCS-8600M and HCS-4800M series main units, ideal for large meetings. It features two SC single-mode fiber interfaces for long-distance data transmission and five conference unit output ports for additional connections. It includes two RJ45 sockets for expanding the system. The extension main unit can also synchronizes power on/off with the main unit. Additionally, dual power inputs ensure automatic switchover to a backup source in case of a power failure, guaranteeing uninterrupted meetings.