1.The main unit of the telephone conference system can connect   75 untis microphone (include one chairman) in one system,it can be extended   to 200 units microphone with expender.
2.It is equipped with three groups of 8P-DIN interface for system connecting.
3.It support the meeting mode: FIFO/LIMIT/FREE .
4.The central processor with telephone conference function. 
5.The system working model can display on LCD.
6.It has the meeting recording output interface.
7.It is equipped with the background music volume and the total volume of   regulator.
8.It has built-in telephone coupler input and output port, it can held a   teleconference .