The SIM800L GSM/GPRS Module is a small, low-cost GSM modem that allows microcontrollers like Arduino, ESP32, or Raspberry Pi to make calls, send/receive SMS, and connect to the internet over 2G (GPRS) networks. This particular version includes a helical antenna for signal reception. ⚠️ Note: You mentioned PTA Non-approved → This means it’s not certified for use in Pakistan’s telecom system, so it may not be legal for commercial deployment there, but it can still be used for educational or experimental projects. 🔹 Key Features: Chipset: SIMCom SIM800L Network support: Quad-band GSM/GPRS (850/900/1800/1900 MHz) Functions: Voice calls, SMS, GPRS (internet via TCP/UDP) SIM card slot: Micro SIM Antenna: Helical spring antenna included (can be swapped with external antenna via IPX connector) Operating Voltage: 3.7V – 4.2V (⚠️ needs a stable supply, often powered from a Li-ion battery or buck converter) Communication: UART (TX, RX) – works with Arduino, ESP32, etc. Current Consumption: Idle: ~20 mA Transmission: Peaks up to 2A (use a capacitor across supply for stability) Size: ~25 mm × 23 mm 🔹 Pinout: VCC → 3.7V – 4.2V input GND → Ground TXD → UART Transmit RXD → UART Receive RST → Reset pin NET → Network status LED 🔹 Applications: GSM-based IoT projects Remote monitoring & control (via SMS/Call) Sending data to servers over GPRS GPS trackers (when combined with GPS module) Smart home automation alerts 🔹 Example Arduino Use: Insert a micro SIM card (with 2G support). Connect module to Arduino (with level shifting if needed). Use AT Commands over Serial to: Send SMS: AT+CMGF=1 → AT+CMGS="number" → “message”. Make a call: ATD+number;