Standard Pi 40PIN GPIO extension header, fits Raspberry Pi series boards
Supports TCP, UDP, PPP, HTTP, FTP, MQTT, SMS, Mail, etc.
Supports GNSS positioning (GPS, BeiDou, GLONASS)
Onboard USB interface, to test AT Commands, get GPS positioning data, and so on
Breakout UART control pins, to connect with host boards like Ardui/STM32
Supports SIM application toolkit: SAT Class 3, GSM 11.14 Release 98, USAT
Onboard voltage translator, 3.3V by default, allows to be switched to 5V via 0 resistor