In IoT applications, Wi-Fi, Bluetooth, 433MHz, ZigBee, Z-Wave, etc. are often used as wireless communication technologies. Among them, 433MHz has a wide range of applications. RF 433MHz refers to the communication frequency band whose wireless operating frequency is centered on 433MHz, and RF 315MHz refers to the communication frequency band whose wireless operating frequency is centered on 315MHz. In addition, there are 915MHz, 868MHz, and other wireless frequencies used for IoT communication. These wireless bands operating below the 1GHz frequency are collectively referred to as Sub-1GHz. Sub-1GHz has better penetration than 2.4GHz, the signal is less attenuated when passing through objects such as walls, and low frequencies can spread better in "corners", which can improve coverage performance.
Note: The connection between Reolink video doorbell cameras and the chimes conforms to RF433.