Technical summary
Powered by 5V, can be powered by USB; for long-term use, it is better to always use a 1A current source. XH2.54-2P connector.
compatible with Arduino, STM32, Raspberry Pi, etc.
TTL 5V and 3V3 interface (yellow pins marked on board), compatible with Arduino, STM32, Raspberry Pi, etc.
On-board RS232 interface, easy for debugging. On the left, white pins.
On-board ring signal LED, on the upper left corner of the SIM900A IC.
On-board reset and restart pins, at the bottom of the SIM900A IC.
Reserved mini IPX connector, but not soldered yet.
Standard SMA antenna connector.
The serial port is protected by TVS and bead circuit, to avoid any current surge or HV.
The SIM circuit has an SMF05C electrostatic discharge IC.
The package includes the antenna and the DC socket.
It does not have an audio power socket on board, which means you cannot hear or talk through the call.
Board size is 5 x 5cm
