1. Support dial-up Internet access, telephone, SMS, TCP, UDP, DTMF, HTTP, and FTP2. Support GPS, BDS, Glonass, and LBS base station positioning3. Onboard USB interface, suitable for testing AT commands and obtaining GPS positioning information4. Onboard CP2102 USB to UART chip, convenient for serial port debugging5. Lead-out module UART control interface, facilitating connection to main control boards like Arduino and STM326. Onboard SIM card slot, suitable for 1.8V or 3V SIM card7. Onboard TF card slot, capable to store files, text messages and other data8. Onboard audio interface and audio decoding chip, applicable to voice operations such as phone calls9. Onboard 2 LED indicators, convenient for operation status supervision of modules10. Onboard level conversion circuit, able to convert 3.3V or 5V working level to 1.8V via jumper cap11. Applicable baud rate range: 300bps ~ 4Mbps (115200bps as default)12. Able to automatically identify baud rate (9600bps ~ 115200bps)
