HL7802 does not respond to AT command

Hi guys,

I want to use the HL7802 to send data via GSM, VGPIO is equal to 1.8V so the model is on but when I send the AT command via UART1 there is no response.

When I check the voltage in UIM1_VCC = 0.6V normally it should be 1.8V.

Hi @Ismaiyl
Welcome you to our community!
Could you please share with me some information as below:

  1. Are you using Windows or Linux operating system ? If Windows operating system, please share with me screenshot of Device Manager

  2. COM port default baud rate is 112500, What baud rate are you using ?

  3. Have you installed the driver for the HL7802 module ? If no, please refer to
    CDM20828_Setup_UART_Driver.zip (3.6 MB)

  4. What firmware version is your HL7802 running? if it’s not the latest and you already checked the step 2 and step 3, please try again with the latest firmware version. Refer to link: https://source.sierrawireless.com/resources/airprime/software/hl7800-firmware/hl78xx-firmware-4,-d-,6,-d-,9,-d-,4/#sthash.Qr5QMdjf.dpbs


Hi @jerdung
Thank you for repaly.

  1. I am using Windows as operating system, I did not communicate with the HL7802 via USB as this is disabled by default, so I used UART1 and sent the command via STM32.

  2. I am using a baud rate of 112500

  3. Is it necessary to install the driver for the HL7802 although I am using the card with STM32 and HL8702?


Hi @Ismaiyl ,
Please refer to how to create communication between HL7802 and STM32 by below link: Connecting STM32 Nucleo-based application to AirVantage - avc - Sierra Wireless