The CS-120CU works as a main unit of the whole system. It provides all inputs and outputs needed to manage complex audio system. A single CS-120CU can be connected with 90 sets of CS-120CH and CS-120DU. With additional power unit CS-120EMU up to 256 sets can be connected. This stand-alone system provides 4 types of conferencing mode, open, over-ride, voice and apply. It meets most conference requirement. Voting function is also provided. Large LCD screen provides detailed information. Soft-key design provides intuitive operation Maximum 4 video cameras can be connected to perform video tracking.