18KHz. Intercom: Sustained, Built-in Microphone. Running Temperature level: -20 ～ 50 ℃. Dimensions: 283.1 * 224.3 * 269mm. Network Ceiling Speaker GEN-6211A03 Power Supply: DC 24V/1A or POE. Interaction Methods: TCP/IP, UDP, SIP, ONVIF. Signal-to-Noise Ratio: > 80dB. Frequency Response: 100Hz https://stephengfavr.blogunok.com/30205260/the-duty-of-an-ip-paging-microphone-in-effective-workplace-communication