1. Support dial-up Internet access, telephone, SMS, TCP, UDP, DTMF, HTTP, and FTP
2. Support GPS, BDS, Glonass, and LBS base station positioning
3. Onboard USB interface, suitable for testing AT commands and obtaining GPS positioning information
4. Onboard CP2102 USB to UART chip, convenient for serial port debugging
5. Lead-out module UART control interface, facilitating connection to main control boards like Arduino and STM32
6. Onboard SIM card slot, suitable for 1.8V or 3V SIM card
7. Onboard TF card slot, capable to store files, text messages and other data
8. Onboard audio interface and audio decoding chip, applicable to voice operations such as phone calls
9. Onboard 2 LED indicators, convenient for operation status supervision of modules
10. Onboard level conversion circuit, able to convert 3.3V or 5V working level to 1.8V via jumper cap
11. Applicable baud rate range: 300bps ~ 4Mbps (115200bps as default)
12. Able to automatically identify baud rate (9600bps ~ 115200bps)