- Power supply by 5V, can be powered by USB, for long term use it is better to still use 1A current power source. XH2.54-2P connector.
- 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 left-top corner of SIM900A IC.
- On Board reset and restart pins, on the bottom of the SIM900A IC.
- Reserved IPX mini connector, but not yet soldered.
- Standard SMA antenna connector.
- Serial port is protected by TVS and beads circuit, to prevent any surging current or HV.
- SIM circuit has SMF05C electrostatics releasing IC.
- Package includes antenna and DC jack.
- Do NOT have audio power jack on board, which means you can not hearing or speaking through the call.
- Board size is 5×5 CM
The attached images show how the use the USB-TTL programmer and RS232 to connect it.
Note: SIM900A is dual band module, may not work for some countries, please check your GSM frequency in your country before buy it.