1. Considering the hardware modification later on, we strong recommend that the hardware design shall pay attention to power supply of the module according to the module Hardware design guide.
2. The module is electrostatic sensitive. When touching the module, please wear electrostatic gloves or an electrostatic wristband, otherwise the oil and sweat on the hands may leave fingerprints on the surface of the module, affecting the appearance and quality of the product.
3.Power supply beyond the range of the module may cause permanent damages.

The recommended voltage value of UNI450 module is 3.8V and its power supply voltage is 3.3v~4.2v.
1. Check whether module is powered on.
2. Check whether these settings is matched: baud rate, flow control.
3. Check whether the UART has a wireless sequence error or poor welding, and whether there is a short circuit to the ground.
4. Check if the voltage levels is matched, default is 1.8v.

If it is a soft restart, there will be no damage, but it might affect the lifecycle of the memory. But If shut down the module suddenly and then power on again fast, there is the risk of memory data lost or whole memory broken.

The network status indicator pin can be used to indicate the working status of the module, please refer to the module hardware design guide.