EC200U-CN: Incoming calls are not reported while AT+CMGS is waiting after Ctrl+Z and Other At command Including AT also not responding

IoT Modules LTE Standard Module
1

Hello Quectel Support,

Module: EC200U-CN

Firmware: EC200UCNAAR03A07M08

I have a reproducible issue:

AT+CMGS=“number”

>

TEST

Ctrl+Z

When SMS cannot be sent (SMS balance/service unavailable), the module waits for a long time.

During this period:

AT → no response

ATH → no response

Incoming call → no RING / +CLIP

DTMF → no response

After +CMS ERROR is finally received, RING, +CLIP and DTMF work again.

I understand that after Ctrl+Z, ESC cannot cancel the operation and the timeout can be up to 120 seconds.

Questions:

Is this behavior expected on EC200U-CN?

How can we reduce the AT+CMGS timeout through the NV configuration?

Is there any supported way to keep incoming calls working while AT+CMGS is waiting?

Is there newer firmware that fixes this issue?

Thank you.

3

Please Reply About my issue ,

I have tested Same in A7670 , it’s not sticking like this after Sms , not Waiting for CMS error imidiatly reporting issue ,

I am expecting same behaviour from. EC200u-cn

4

Hi @rajeshkolhe110

Based on the behavior described, this is expected behavior for the EC200U-CN. After Ctrl+Z is sent, the module waits for the network response for the SMS submission, and the maximum response time for AT+CMGS can be up to 120 seconds, depending on the network.

During this period, the AT command interface is occupied by the ongoing SMS operation, so commands such as AT and ATH, as well as URCs such as RING and +CLIP, may not be processed until the AT+CMGS operation is completed and the final +CMS ERROR or other final response is returned.

Regarding your questions:

  1. Can the AT+CMGS timeout be reduced through NV configuration?
    Currently, there is no supported NV configuration or AT command to reduce the 120-second AT+CMGS network timeout.

  2. Can incoming calls remain functional while AT+CMGS is waiting?
    You may consider using CMUX (Multiplexing Mode), which provides multiple virtual channels over the same physical UART interface. This can allow one channel to handle the SMS operation while another channel is used for URCs and call-related operations.

    You may also refer to the RI configuration, such as AT+QCFG="urc/ri/ring", for hardware-level incoming call indication.

  3. Newer firmware
    I have provided the latest available firmware to you via email. Please check and test with the provided firmware to see whether the behavior is improved.

Please let us know the test results after trying the above suggestions.

Thank you and have a nice day!