Rectify SIM800C GSM Modem Communication Issue
Budget: ₹600 – ₹5,000 INR
Project Title:
Resolve Compatibility Issue: Customized SIM800C GSM TTL Modem Not Communicating with Target Device
Project Description:
I have customized a SIM800C GSM Serial TTL Modem for use in GSM applications (SMS and data). The module is designed to interface directly with microcontrollers via TTL levels.
Modifications I Made to the Original Design:
Removed MAX232 IC to keep TTL-level communication.
Added RTC Module (on the same PCB) for time-stamping SMS data.
All SIM800C basic functionalities (SIM Slot, Network LED, Antenna SMA, etc.) are intact.
The module works perfectly standalone (AT commands work fine via serial terminal).
TTL Communication (9600 baud rate) with Arduino works fine in testing.
Problem Statement:
When interfaced with our existing embedded device, this customized SIM800C modem fails to communicate/respond correctly.
Objective:
I need an expert to:
Analyze the customized SIM800C Modem design (Schematics & PCB) for potential hardware incompatibilities.
Guide/Modify to ensure proper UART communication compatibility with our existing embedded device.
Suggest/Implement any level shifting, buffering, or signal conditioning circuits if needed.
Validate if RTC addition could be affecting communication lines (hardware-wise).
Assist in AT Command debugging and timing issues (optional but preferred).
Provide guidance for successful integration with our product.
Module Details:
SIM800C Serial TTL Modem
Power Supply: 9V 2A Adapter
UART TTL Interface (3.3V / 5V logic compatibility)
AT Commands Only Operation
Baud Rate: 9600
RTC integrated on PCB (No external interface)
MAX232 Removed for direct TTL
Resolve Compatibility Issue: Customized SIM800C GSM TTL Modem Not Communicating with Target Device
Project Description:
I have customized a SIM800C GSM Serial TTL Modem for use in GSM applications (SMS and data). The module is designed to interface directly with microcontrollers via TTL levels.
Modifications I Made to the Original Design:
Removed MAX232 IC to keep TTL-level communication.
Added RTC Module (on the same PCB) for time-stamping SMS data.
All SIM800C basic functionalities (SIM Slot, Network LED, Antenna SMA, etc.) are intact.
The module works perfectly standalone (AT commands work fine via serial terminal).
TTL Communication (9600 baud rate) with Arduino works fine in testing.
Problem Statement:
When interfaced with our existing embedded device, this customized SIM800C modem fails to communicate/respond correctly.
Objective:
I need an expert to:
Analyze the customized SIM800C Modem design (Schematics & PCB) for potential hardware incompatibilities.
Guide/Modify to ensure proper UART communication compatibility with our existing embedded device.
Suggest/Implement any level shifting, buffering, or signal conditioning circuits if needed.
Validate if RTC addition could be affecting communication lines (hardware-wise).
Assist in AT Command debugging and timing issues (optional but preferred).
Provide guidance for successful integration with our product.
Module Details:
SIM800C Serial TTL Modem
Power Supply: 9V 2A Adapter
UART TTL Interface (3.3V / 5V logic compatibility)
AT Commands Only Operation
Baud Rate: 9600
RTC integrated on PCB (No external interface)
MAX232 Removed for direct TTL