Feature: 1. 【Wireless Intercom System】: This wireless intercom phone operates at 433MHz and offers stable digital transmission over long distances. It doesn\u0027t require any wiring, network, or additional fees, making it a plug-and-play device with built-in signal. 2. 【Supports Multiple Devices】: The main unit and sub-units can support up to 99 devices for intercommunication. Each unit displays its own ID number, ensuring secure digital encryption and preventing code interference. 3. 【Adjustable Call Features】: The device offers incoming call display, adjustable call volume, and one-touch calling. It also features a one-touch broadcast function and 38 different ringtones with adjustable volume. 4. 【Long-Range \u0026amp; High-Quality Sound】: The wireless transmission distance reaches up to 1 kilometer, with clear sound quality for two-way conversations. The device supports simultaneous talking without the need to alternate pressing buttons, ensuring stable performance and high-fidelity sound. 5. 【Versatile Application】: This wireless intercom phone is suitable for a wide range of settings, including offices, factories, hotels, KTVs, hospitals, and other public venues. The device can penetrate up to 8 walls within a room, making it a reliable communication tool for any environment. Specification: Power Supply Method: Direct power supply, USB interface 5V2A DC Style: Host, Extension (optional) 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 operation) 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 . Package List: 1 x Intercom Telephone Host1 x Intercom Telephone Extension2 x Adapter2 x Supply Cord1 x English Instruction Manual Note: The real color of the item may be slightly different from the pictures shown on website caused by many factors such as brightness of your monitor and light brightness. Please allow slight manual measurement deviation for the data.