1. Every main unit itself can provide system accessing up to 60 contribution units and can be expanded to over 200 with expansion unit; 2. Support many kinds of meeting mode: free mode, FIFO mode, limit mode Free mode: the microphone will open when the speaker start addressing and after addressing it can be turned off or the chairman can turn off it in advance FIFO mode: the amount of the active delegate unit can be 1 to 20, when a new delegate unit opened the previous one will turned off automatically, the rest may be deduced by analogy; (There is no limitation for the chairman unit) Limit model: the quantity of the active delegate unit can be 1 to 20, besides there is a microphone which was turned off, or else the new microphone can not be opened to address. (There is no limitation for the chairman unit) 3. Support each microphone readjust preinstall seat independently 4. Achieve all-wave control by ACS102RF intelligent telecontrol or ACS400VM panel of intelligent visual track host machine, included saving the preinstall seat which move together with microphone, the intelligent telecontrol of ACS102RF can lock the camera and resume visual track function;