SIM 900A GSM GPRS Modem TTL with Antenna

The GSM-900 GSM/GPRS Module, featuring the SIM900A chip, is a compact and versatile communication module that brings GSM and GPRS connectivity to your electronics projects. It enables devices to make and receive voice calls, send and receive SMS messages, and connect to the internet using GPRS data services—just like a basic mobile phone. With the ability to connect a microphone and speaker, this module even allows real-time voice communication through your microcontroller-based system.

The SIM900A is a dual-band GSM/GPRS engine operating at EGSM 900MHz and DCS 1800MHz, making it ideal for use in many parts of Asia, including India. It supports GPRS multi-slot Class 10 and Class 8, and offers compatibility with GPRS coding schemes CS-1 to CS-4, ensuring flexible and reliable data transmission. Whether you’re working on IoT applications, security systems, remote monitoring, or smart automation, this module provides a stable and cost-effective communication solution.

The module communicates with microcontrollers using a UART (Serial) interface, making it easy to integrate with popular development boards like Arduino, Raspberry Pi, ESP32, STM32, and more. With only two wires (TX and RX), you can start sending AT commands to the module and receive data effortlessly.

It operates on a 4.0V DC power supply and requires a current of up to 2A during transmission peaks, especially while connecting to the GSM network or during voice calls. It’s important to ensure proper power regulation as exceeding 4.5V can damage the module permanently.

Commonly used in IoT devices, automotive systems, robotics, vending machines, GPS trackers, and remote servers, the GSM-900 SIM900A module offers a reliable, compact, and accessible solution for GSM/GPRS-based communication in embedded systems.

Specifications

• The onboard two set power supply interface VCC5 5V power supply, VCC4 interface, 3.5–4.5V power supply, optional power on self starting (default) and control start.
• The onboard SMA (default) and IPX mini antenna interface, SIM900A interface reserved reset.
• The size of the module is 49*50, all the new and original device.
• The computer can give early computer debugging USB module power supply,
  a very large amount of data under the condition of the recommended current more than 1A.
• Standby dozens of MA data can be set to provide dormancy, dormancy of 10MA low power.
• The serial port circuit: support for 3.3V single chip microcomputer.
• TTL serial port support3.3 and 5V single chip microcomputer.
• The SIM card circuit to increase the SMF05C ESD chip.
• Antenna circuit: guarantee short and straight, so as to ensure the signal strength.
• PCB display screen printing mark: each interface, convenient development two times,
  the SIM900/A hardware is completely follow the design when the design manual.
• Two power supply interface: VCC5, 5V DC above 1A.
• Computer 5V power supply can be early computer USB.
• DC long data circuit over larger recommended 5V1A.
• VCC4, 3.5–4.5V power supply, ibid., suitable for lithium battery.
• Control pin all leads.
• A TTL level, compatible with 3.3V and 5V.
• The two antenna interface, the default SMA straight head, connector for IPXmini antenna.
• One way of speech interface, the way Mike interface.

Pin Description

• GND – GNDSIMR SIM900A RXD, TTL level,
• can not be directly connected to the 232 levelSIMT SIM900A TXD, TTL level,
• can not be directly connected to the 232 levelRST – SIM900A reset,
• active lowVCC_MCU when the SIM900A module and 5V TTL level communication,
• this pin is connected to DC 5V;
• when the level of communication of SIM900A and 3.3V TTL, this pin is connected to DC 3.3V.
  VCC5—-DC 5V input.
  VCC4——DC3.5–4.5 input
• Onboard Resources: Serial port circuit(with protection)
• Antenna interface circuit(SMA bend female port)SIM card circuit
• (flip SIM slot)4*3.5 fixture hole 4pcsSIM900A serial port output terminal
• Size:49mm x 47mm
• Net Weight:28gWeight: 38g

Package Includes

• 1 x SIM900A Module
• 1 x Antenna