... system normalf) Student machines without coding,andcan exchange, plug and play, making the system simplerand convenient.6,Low-carbon, ... dB (0dB = 20uPa The) (input power = 1mW);Electrical Impedance: 32Ω ± 20%;The characteristics of sound pressure level (sensitivity): the ≥ ... packet transmission protocol, and audio transmission optimization;Triple-play network mode, the audio exchange host to students ...