18KHz. Intercom: Supported, Integrated Microphone. Running Temperature: -20 ～ 50 ℃. Measurements: 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 Proportion: > 80dB. Frequency Reaction: 100Hz https://radio47766.buyoutblog.com/30052814/why-an-ip-paging-system-is-vital-for-modern-companies