How to Use XTEND-DIGI-MODEM: Examples, Pinouts, and Specs

The XTEND-DIGI-MODEM is a long-range, low-power wireless modem designed for reliable communication in remote applications. Operating in the 900 MHz frequency band, it provides robust connectivity over extended distances. With support for various data rates, the XTEND-DIGI-MODEM is ideal for Internet of Things (IoT) and telemetry projects, where reliable data transmission is critical. Its versatility and ease of integration make it a popular choice for industrial automation, environmental monitoring, and agricultural systems.

• IoT networks for remote sensor data collection
• Telemetry systems for industrial and environmental monitoring
• Agricultural automation, including irrigation control
• Long-range wireless communication in remote areas
• Machine-to-Machine (M2M) communication

The XTEND-DIGI-MODEM has a 10-pin interface for power, communication, and control. Below is the pinout:

1. Power Supply: Connect the VCC pin to a regulated power source (2.8V to 5.5V) and the GND pin to the ground of your circuit.
2. UART Communication: Connect the TX pin of the modem to the RX pin of your microcontroller, and the RX pin of the modem to the TX pin of your microcontroller.
3. Antenna: Attach a compatible 900 MHz antenna to the RP-SMA connector for optimal performance.
4. Configuration: To enter configuration mode, pull the CONFIG pin high. Use Digi's XCTU software or AT commands to configure the modem settings.
5. Reset: To reset the modem, pull the RESET pin low momentarily.
6. Flow Control (Optional): If using hardware flow control, connect the RTS and CTS pins to the corresponding pins on your microcontroller.

• Antenna Placement: Ensure the antenna is placed in an open area, away from metal objects, to maximize range.
• Power Supply: Use a stable power source to avoid communication issues caused by voltage fluctuations.
• Baud Rate Matching: Ensure the baud rate of the modem matches the baud rate of your microcontroller or PC.
• Line of Sight: For maximum range, maintain a clear line of sight between the transmitter and receiver.
• Configuration: Use Digi's XCTU software for easy configuration of parameters like channel, network ID, and data rate.

Below is an example of how to connect and use the XTEND-DIGI-MODEM with an Arduino UNO:

#include <SoftwareSerial.h>

// Define RX and TX pins for SoftwareSerial
SoftwareSerial xtendModem(10, 11); // RX = Pin 10, TX = Pin 11

void setup() {
  // Start the serial communication with the modem
  xtendModem.begin(9600); // Ensure this matches the modem's baud rate
  Serial.begin(9600); // For debugging via Serial Monitor

  // Send a test message to the modem
  xtendModem.println("Hello, XTEND-DIGI-MODEM!");
  Serial.println("Message sent to modem.");
}

void loop() {
  // Check if the modem has sent any data
  if (xtendModem.available()) {
    String receivedData = xtendModem.readString();
    Serial.print("Received from modem: ");
    Serial.println(receivedData);
  }

  // Check if the user has sent data via Serial Monitor
  if (Serial.available()) {
    String userInput = Serial.readString();
    xtendModem.println(userInput); // Send user input to the modem
    Serial.println("Message sent to modem.");
  }
}

1. No Communication with the Modem

   • Cause: Incorrect baud rate or wiring.
   • Solution: Verify the baud rate settings and ensure TX and RX pins are correctly connected.

2. Limited Range

   • Cause: Obstructions or improper antenna placement.
   • Solution: Ensure a clear line of sight and proper antenna orientation.

3. Modem Not Entering Configuration Mode

   • Cause: CONFIG pin not pulled high.
   • Solution: Check the CONFIG pin connection and ensure it is pulled high during power-up.

4. High Power Consumption

   • Cause: Continuous transmission or high data rate.
   • Solution: Optimize the data rate and use sleep modes when possible.

• Q: Can I use the XTEND-DIGI-MODEM with a 3.3V microcontroller?

  • A: Yes, the modem supports a voltage range of 2.8V to 5.5V, making it compatible with 3.3V systems.

• Q: How do I update the firmware?

  • A: Use Digi's XCTU software and follow the firmware update instructions provided in the software.

• Q: What is the maximum data rate supported?

  • A: The modem supports data rates up to 115.2 kbps.

• Q: Can I use multiple modems in the same network?

  • A: Yes, you can configure multiple modems with the same network ID and channel for communication.

This documentation provides a comprehensive guide to using the XTEND-DIGI-MODEM effectively in your projects.