RM500U-CNV TCP receive data loss

IoT Modules 5G Module
,
1

Hello.
We have RM500U-CNV module connected throught serial port to esp32. We need to make mqtt connection using SSL connection.

  1. The buffered TCP connection to the server is ok and the server is receiving the messages.
  2. When server send the message (SSL hello message) larger than 2048 bytes, it is truncated. For example if it sends 2401 bytes, only 2048 arrives.

Is there some limitation for incomming data size? how can we make the SSL connection with this modem?

The commands and server responses:


AT+QIOPEN=1,1,"TCP","our.server..com",8883,0,0
OK
+QIOPEN: 1,0

AT+QISEND=1,138
> .......
SEND OK

+QIURC: "recv",1

AT+QIRD=1,1500
+QIRD: 1500
AT+QIRD=1,99
+QIRD: 99
AT+QIRD=1,1029
+QIRD: 449
AT+QIRD=1,585
+QIRD: 0

As you can see, in SUM 2048 bytes arrived.
Thank you.
Jaroslav

2

Dear @chefotm
Please share your current firmware.

What did you test? TCP or MQTT?

3

Hello Silvia. Our modem:

//Manufacturer
 AT+CGMI
   Quectel

//Firmware
AT+CGMR
  RM500UCNVAAR03A02M2G_01.001.01.001

//Model
AT+CGMM
  RM500U-CNV

We tested the TCP connection in transparent and buffered mode (AT+QIOPEN). Both working fine until the incoming packet payload is less than 2048 bytes long . If the payload exceeds 2048 bytes, the modem start to ignore the rest of incoming payload from server (for example when we are trying to start the SSL connection and the server send the certificate). .

According to the AT command manual for the RM500U-CNV, there is no MQTT client in the modem, or are we wrong?

Thank you very much.