18KHz. Operating Temperature level: -10 ～ 50 ℃. Measurements: 440x300x44mm. Zone Combining Digital Amplifier NBS-2301 Power Supply ： AIR CONDITIONING 220V, 50Hz. Power ： 130W ， 260W ， 360W ， 550W ， 700W. Interaction Protocol ： HTTP, TCP/IP, UDP, ARP, ICMP, IGMP. Signal-to-Noise Proportion ：. Mic Input 01: ≥ 65dB,. https://lanejeuei.iyublog.com/29503084/discover-the-conveniences-of-using-an-ip-speaker-for-clearer-announcements