Gsmneo -

| GSMNeo Pin | Connect to | |------------|-------------| | VCC | 3.8V–4.2V (peak current up to 2A) | | GND | Common ground with microcontroller | | TXD | Microcontroller RX (use level shifter if 5V logic) | | RXD | Microcontroller TX (level shift) | | PWR_KEY | Pull low for 1–2 seconds to power on |

AT → OK (module responds) ATE0 → Echo off AT+CPIN? → Ready (if SIM inserted) AT+CREG? → +CREG: 0,1 (registered) AT+CSQ → Signal quality (rssi) AT+CMGF=1 → SMS text mode A. Remote Alarm via SMS Connect a sensor (PIR, water leak, temp) to a microcontroller. When triggered, GSMNeo sends: gsmneo

⚠️ power GSMNeo directly from an Arduino’s 5V pin – it will cause resets. Use a dedicated 2A+ regulator or Li-ion battery. 3. Basic AT Command Sequence After power-on and waiting ~5 seconds for network registration: | GSMNeo Pin | Connect to | |------------|-------------|