Wireless Intercom Phone Extension Supports Multiple Devices Adjustable Volume Wireless Intercom System Power Supply Method: Direct power supply, USB interface 5V2A DC Style: Extension Working Temperature: -10 ° C to 55 ° C Transmission Distance: Approximately 1000 meters of open space, 5-40 meters of partition walls, floors 1-8 Working Power: 0.5W Working Frequency: 410MHz~460MHz Working Hours: plug-in work Music Ringtones: 38 ringtones Volume: Level 3 adjustment (standby machine volume adjustment key) Call Sound: Level 3 adjust call size (adjust volume key during call operating) Button: 10 numeric buttons, 1 call button, 1 settings button Host Interconnection, 2-100 interconnected hosts and extensions, supporting up to 100 interconnections Working Current: 400mA Transmission Power: <30dbm Backup Current: 70mA Receiving Sensitivity: >-100dbm Product Size: 170 * 110 * 54mm/6.7 * 4.3 * 2.1inch Points for Attention: 1. If the call bell rings only once or the call is interrupted, it indicates that the distance is far. Please adjust the distance 2. Unclear call, noise, automatic interruption - indicates a long distance. If there is an interference source, please adjust the distance 3. Unable to make calls - Check if network pairing is successful 4. The screen flashes and the power indicator light flashes frequently - indicating that the power adapter is unstable. Please replace it with a regular 5V2A power supply 5. Whispering sound - indicates that the distance is too close 6. If the screen is not lit and the power indicator light is not on, it indicates that the power switch has not been turned on 7. Only a beep sound during the call indicates that the machine being called has not hung up properly 8. Cannot broadcast - This indicates that it is not the first host in the code (press the number<3>key), which is the code transmitter