EC25 large size data upload

I am using EC25 and I want to POST a large amount of data (more than 50MB) to the REST API. The following patterns are possible to achieve this. None of the methods could meet my expectation for the reasons mentioned below. If anyone knows the proper way to implement this in such a case, please let me know.

Note that the MCU is STM32F7, and the MCU and EC25 are connected via USB.

  1. Using AT+QHTTPPOST.
  2. Using AT+QISEND.

The AT+QHTTPPOST command can only send 1MB of data at a time. Therefore, if I wanted to send 50MB of data, I would have to hit the REST API 50 times and concatenate the data 50 times on the server side. This is a specification that is out of line with the principles of the Web, and we do not want to adopt it.

AT+QISEND is a command for sending TCP, but if we create an HTTP packet in the MCU, split the packet, and forward it with AT+QISEND, the HTTP request will fly from the EC25 to the server. In this way, the data could be transferred to the server as a single HTTP packet, unlike 1. However, we found that there were two problems as follows. AT+QISEND can only send 1460 bytes of data at a time. Therefore, when sending 50MB of data, it is necessary to send AT+QISEND more than 3000 times between MCU and EC25. This communication may succeed in sending 50MB data to the server, but the EC25J overflows its buffer or hangs up about once every five times, making it useless.

I thought it would be right to handle such large data as a file, so I tried AT+QHTTPPOSTFILE. This command requires a file to be transferred from the MCU to the EC25 in advance, which can be done with AT+QFUPL or AT+QFWRITE, but the file transfer from the MCU to the EC25 was very slow, taking almost an hour to send 50MB.


Hello nash, thanks for your question
The built-in protocol stack of the EC25 module does not have a method for faster uploading of big data to the HTTP server, or you can try to use an external protocol stack for transmission, thank you.

Hello Duncan, thank you for your reply.
The build-in protocol stack means AT commands which start from AT+Q?
And please tell me an detail of external protocol stack for transmission.

Thank you!

Hello nash, thank you for your feedback
There are corresponding AT commands for using the built-in protocol stack. You can contact your local FAE or agent to obtain related documents, or send an email to If you decide to use an external protocol stack for data transmission, this needs to be developed by the customer. We currently have no documentation for external protocol stack development, thank you.