SIM800C GPRS GSM Module MicroSIM Card Core Board Quad-band TTL Serial Port.
The SIM800C is a quad-band GSM/GPRS cellular communication module made by SIMCom, widely used in IoT, remote monitoring, and embedded projects for voice, SMS, and data.
SIM800C Vs SIM800L
To work the same way, SIM800C has a BOOT pin, connect it to GND for the module to boot right away when powered. Otherwise it could be connected to MCU pin and used to turn OFF and ON the module to save power. For the SIM800L, this pin is already connected to the GND.
Key Specifications
- Frequency Bands: Quad-band GSM/GPRS (850, 900, 1800, and 1900 MHz)
- GPRS Data Speed: GPRS multi-slot class 12, up to 85.6 kbps (uplink and downlink)
- Operating Voltage: 3.4V to 4.4V DC (typically 4.0V; peak currents require a steady, high-current supply)
- Communication Interface: UART (TTL serial), plus optional USB-to-serial variants using chips like CH340
- Control Protocol: Standard AT commands (3GPP TS 27.007, 27.005, and enhanced SIMCom command sets)
- Embedded Stacks: TCP/IP, UDP, HTTP, FTP, MMS, and DTMF support
- Audio & Peripherals: Analog audio input/output (microphone and speaker pins), RTC, ADC, and (U)SIM card interface (1.8V/3V)
Common Basic AT Commands for Testing
• AT — Checks communication with the module (returns OK)
• AT+CPIN? — Verifies if the SIM card is inserted and unlocked
• AT+CSQ — Checks signal strength
• AT+COPS? — Queries current network operator registration
• AT+CMGF=1 — Sets SMS mode to text mode
• AT+CMGS="phone_number" — Sends an SMS message
Critical Power Requirements
The most common mistake with the SIM800C is powering it directly from the Arduino's 5V or 3.3V pins. The SIM800C requires 3.4V to 4.4V (ideally 4.0V) and can draw up to 2A of peak current during network transmission bursts.
Resources:
1. SIM800C Module Testing with Arduino
2.