The SIM800L is a compact GSM/GPRS module supporting 850/900/1800/1900MHz bands. It communicates via UART using AT commands and enables SMS, voice calls, and GPRS data over a cellular network.
| Pin | Name | Function | Type |
|---|---|---|---|
| VCC | VCC | 3.4V–4.4V power (use LiPo) | PWR |
| GND | GND | Ground | GND |
| TXD | TXD | UART TX from module | BUS |
| RXD | RXD | UART RX to module | BUS |
| RST | RST | Reset, active low | I/O |
| DTR | DTR | Sleep control | I/O |
| NET | NET | Network LED status | I/O |
| STATUS | STATUS | Module status LED | I/O |