Ks0259 keyestudio PN532 NFC/RFID Controller Shield
keyestudio 16-channel Servo Motor Drive Shield
This is a GPRS / GSM Arduino expansion boarddeveloped by Keyes. It is a shield module with frequency of EGSM 900MHz / DCS 1800MHz and GSM850 MHz / PCS 1900MHz, integrated with GPRS, DTMF and other functions. It supports DTMF, when the DTMF function is enabled, you can get the character feedback from the conversion of button pressed down during the call, which can be used for remote control.
It is controlled by the AT command, you can directlystart its function through the computer serial port and Arduino motherboard. The SIM800C GPRS Shield board has abuilt-in SIM800H chip with good stability.