At the hardware level, each phone conference chip has the following limit: l Each phone conference chip supports 1 ~ 32 channels (4M clock input); l Supports up to 1 to 29 conferences per chip; L can set each The input and output gain / attenuation of a channel (0 ~ 15dB, step length 1db); L can generate overflow information; L can query the status of each channel. Note: When using 2 telephone conference chips, if you need to add 1 or more channels of the chip 1 to the meeting of the chip 2, you need an additional occupancy chip 1 and the chip to two channels as two chips. Connection channel, if it is true to be implemented, it may increase the complexity of the background software design.