Key Features:

• Quad-Band Operation:
  The SIM900D operates in four frequency bands:

  • 850 MHz

  • 900 MHz

  • 1800 MHz

  • 1900 MHz
    This allows the module to work with GSM networks across a wide range of global carriers.

• GPRS Multi-Slot Class 10/8:
  The module supports General Packet Radio Services (GPRS) with multi-slot class 10 or 8, enabling fast and reliable data transfer over the GSM network.

• GPRS Class B Mobile Station:
  Supports GPRS Class B, allowing for both data transmission and voice services to be used simultaneously.

• Power Output:

  • Class 4 (2 W) at 850/900 MHz

  • Class 1 (1 W) at 1800/1900 MHz
    This refers to the transmission power for maintaining a strong and stable connection on different network frequencies.

• GSM Phase 2/2+ and PCS Compatibility:
  Fully compatible with GSM Phase 2/2+ and PCS (Personal Communication Services) networks, ensuring wide network compatibility.

• Control via AT Commands:

  • Standard Commands: Compatible with GSM 07.07 and 07.05 standards for communication control.

  • Enhanced Commands: Uses SIMCOM AT commands, which offer advanced features and better control.

• Short Message Service (SMS):
  Supports SMS functionality, allowing for the sending of small amounts of data over the GSM network, including the ability to send messages in raw hexadecimal format.

• Integrated TCP/UDP Stack:

  • The module includes built-in TCP/UDP stack, allowing you to send data over the internet, for example, uploading to a web server.

• PSTN Compatibility:
  It is also compatible with Public Switched Telephone Networks (PSTN), enabling voice communication.

• Selectable Serial Port:
  You can choose which serial port to use for communication with the module, offering flexibility in your design.

• Audio Support:

  • Speaker and Headphone Connectors:
    The module provides connectors for audio output, allowing it to be used in voice applications like making calls or voice data transfer.

• Low Power Consumption:

  • The SIM900D operates in sleep mode consuming as little as 1.5mA, which is beneficial for battery-powered and low-power applications.

Technical Specifications:

• Operating Voltage:

  • Typically, 3.4V to 4.4V, commonly supplied with a 5V regulator for stable operation.

• Data Transmission Rate:

  • Supports GPRS multi-slot class 10 for fast data transmission speeds. This is sufficient for most IoT applications like sending sensor data to a server.

• SMS Format:

  • The module supports SMS in text mode or PDU (Protocol Data Unit) mode, which allows for raw hexadecimal data transfer.

• Supported Protocols:

  • GPRS: For packet-switched data transmission.

  • TCP/UDP: Allows internet connectivity for web communication.

  • SMS: Allows sending and receiving short messages.

• Audio Features:

  • Speaker/Headphone Output: Can be used for making voice calls or audio communication.

  • Microphone Input: Supports voice data input for communication.

Applications:

The SIM900D GSM/GPRS module is commonly used in various applications, including:

• IoT Projects: For remote communication and data transfer, such as transmitting sensor data to a server.

• Remote Control Systems: Can be used for controlling devices remotely via SMS commands.

• Tracking Systems: Used in GPS and tracking applications for real-time location updates over GSM networks.

• Embedded Voice Applications: Can be used in devices that require voice communication or audio output.

Summary:

The SIM900D GSM/GPRS module is a robust solution for adding GSM connectivity to your embedded projects. With support for quad-band operation, GPRS data transfer, SMS functionality, and built-in internet protocols like TCP/UDP, it is suitable for a wide range of IoT, remote control, and communication applications. Its low power consumption, compatibility with PSTN, and advanced control via AT commands make it a versatile and reliable choice for both beginners and experienced developers.