How to Use sim 800l: Examples, Pinouts, and Specs

The SIM800L is a compact and versatile quad-band GSM/GPRS module that enables cellular communication in a wide range of applications. It allows devices to communicate over GSM/GPRS networks, making it ideal for Internet of Things (IoT) projects, remote monitoring systems, and mobile communication solutions. Common applications include SMS messaging, data transmission, and voice calls.

• Frequency Bands: Quad-band 850/900/1800/1900MHz
• Supply Voltage: 3.4V to 4.4V (Typical 4.0V)
• Operating Current: Approx. 1mA (sleep mode), 300mA (transmission mode)
• Temperature Range: -40°C to +85°C
• Sensitivity: -107dBm (GSM 850/900MHz), -106dBm (DCS/PCS)
• Data Transmission: GPRS multi-slot class 12/10, GPRS mobile station class B

1. Power Supply: Connect a stable power source capable of delivering 2A during transmission bursts to the VCC and GND pins. A voltage regulator may be necessary to ensure the voltage remains within the specified range.

2. Serial Communication: Connect the RXD and TXD pins to the corresponding TX and RX pins of your microcontroller (e.g., Arduino). Remember to cross-connect RX to TX and TX to RX.

3. Antenna: Attach an appropriate GSM antenna to the antenna pad to ensure proper signal reception and transmission.

4. SIM Card: Insert a micro SIM card into the SIM card holder, ensuring the card is activated and has the appropriate services for your application.

• Power Requirements: The SIM800L requires a peak current of up to 2A during transmission. Ensure your power supply can handle this requirement without voltage drops.

• Level Shifting: If interfacing with a 5V microcontroller, use a level shifter for the RX and TX lines to avoid damaging the SIM800L.

• Baud Rate: Configure the serial communication to the correct baud rate, typically 9600 bps for the SIM800L.

• Network Registration: Ensure the module has registered to the network before attempting to send or receive data.

• AT Commands: Use AT commands to control the module. Familiarize yourself with the SIM800L AT command set for effective communication.

#include <SoftwareSerial.h>

SoftwareSerial sim800l(10, 11); // RX, TX

void setup() {
  // Begin serial communication with Arduino and SIM800L
  sim800l.begin(9600);
  Serial.begin(9600);

  // Set SIM800L module to SMS mode
  sim800l.print("AT+CMGF=1\r");
  delay(1000);

  // Set module to send SMS data to serial out upon receipt 
  sim800l.print("AT+CNMI=2,2,0,0,0\r");
  delay(1000);
}

void loop() {
  // Check if the SIM800L module is sending a message
  if(sim800l.available()){
    Serial.write(sim800l.read());
  }
  // Check if the Arduino terminal is sending a message
  if(Serial.available()){    
    sim800l.write(Serial.read());
  }
}

• Power Supply Inadequacy: If the module frequently restarts or does not power up, check your power supply for sufficient current output.

• Signal Strength: Poor signal strength can lead to communication failure. Ensure the antenna is properly connected and positioned.

• SIM Card Issues: If the SIM card is not recognized, ensure it is correctly inserted and the SIM pin is disabled.

• Power Supply: Use a high-quality power supply with a large capacitor (e.g., 1000µF) to smooth out power supply fluctuations.

• Level Shifting: Use a bidirectional level shifter for safe communication between the SIM800L and a 5V microcontroller.

• AT Command Testing: Use a serial monitor to manually send AT commands to the SIM800L for testing and debugging.

Q: Can I use the SIM800L for internet connectivity? A: Yes, the SIM800L supports GPRS for internet connectivity, but it is limited to 2G speeds.

Q: How do I know if the SIM800L is connected to the network? A: You can send the AT command AT+CREG? to check network registration status.

Q: What is the default baud rate of the SIM800L? A: The default baud rate is typically set to 9600 bps.

Q: Can I make voice calls with the SIM800L? A: Yes, the SIM800L is capable of handling voice calls in addition to SMS and data transmission.