... and hundreds of classroom, you only need to give one 2.4GHz transmitter to each teacher, whatever which room the teacher in ... be connected with PC,central control,USB system.5.Five line wired MIC input with 6V power supply6.Certificate:ISO 9001 ... :20007.Three line audio input,A line 2.4G wireless MIC input8.A line advanced audio input, echo, volume and ...