Issue with A9G Module: Receiving Data but Unable to Send Commands

Hello everyone,

I am currently working with an A9G GSM/GPS module and encountering a strange issue. The module is able to receive data from my microcontroller, but it is unable to send commands. Below is a description of my setup, and I would appreciate any help or suggestions.

My Setup:A9G Module (as shown in the attached image)Power Supply: 3.7V-4.2V, providing sufficient current (I verified it can handle up to 2A)SIM Card: Properly seated and activated with a data planWiring:TX (Yellow Wire): Connected to URX pin on the A9GRX (Green Wire): Connected to UTX pin on the A9GRed Wire: Connected to VCCBlack Wire: Connected to GND Communication Baud Rate: Set to 115200 bps Using a USB-to-Serial Adapter for communication

Issue Description:

I can receive data (such as responses from the module) without any issues.However, I am unable to send AT commands to the module. The module does not respond to commands such as AT, and no error messages appear.

https://wiki.dfrobot.com/A9G_Module_SKU_TEL0134