Using FM communication method, there are 37 communication frequency points and 3 broadcast frequency points. It can effectively avoid some frequency interference. It is not recommended to use through walls. If it is a hollow wooden wall, you can try it out.

It only requires other certifications for the product, such as FCC, CE, and wireless, without further certification.

Shielding can shield the interference of external signals on the module's own circuit and also prevent the interference of the module's own circuit with RF.

Single mode is the abbreviation for single mode module, commonly used in low-power Bluetooth. It is a Bluetooth version that mainly runs modules on the Bluetooth protocol stack.

The dual mode module has two built-in versions and can run two sets of protocol stack modules, which are compatible with standard Bluetooth and support BLE Bluetooth. Its characteristic is that Android can only use version 3.0, and the IOS system can only use the low-power Bluetooth version.

Serial port is one of the most commonly used peripheral interfaces for Bluetooth modules, used for data transmission or command control of Bluetooth modules.

First, power up the Bluetooth module (3.3V), then short connect TX and RX, search for the Bluetooth serial port module through a computer or phone, and pair it up. Then, data can be sent and received through the serial port software, which can test whether the Bluetooth serial port module is working properly.

No, just treat the Bluetooth serial port module as a transparent serial peripheral for transmission. After pairing with the Bluetooth serial port module on a computer or mobile phone, the corresponding Bluetooth virtual serial port and Bluetooth serial port module can be opened through an application program for communication. The Bluetooth module can be connected to other peripherals with serial ports, such as a microcontroller or another computer.

The Bluetooth serial port module is based on the Bluetooth protocol and implements SPP (serial port application). Other applications such as A2DP for audio are not supported. However, USB's Bluetooth adapter (dongle) has various applications, such as file transfer, virtual serial port, voice, and so on.

Traditional Bluetooth, also known as classic Bluetooth, can achieve audio transmission, transfer large files, and consume a lot of power; BLE Bluetooth, also known as low-power Bluetooth, only supports data transmission and is suitable for short distance data collection, data transmission, and intelligent control of the Internet of Things.

Bluetooth beacon is a hardware device based on the low-power Bluetooth BLE (Bluetooth 4.0 or above) broadcast protocol, compatible with the ibeacon protocol or eddystone. Bluetooth beacons typically use small, portable devices that can be installed in different locations, such as shops, museums, airports, etc. Through Bluetooth beacons, users can obtain real-time location related information, navigation services, personalized push notifications, and more.