EC21 (Revision EC21EUGAR06A04M4G) – Is WebSocket connection possible via AT commands?

IoT Modules LTE Standard Module
1

Hello,

I am using a Quectel EC21 (Revision: EC21EUGAR06A04M4G) module.
The server I need to connect to only supports MQTT over WebSocket (wss://).

When I try with AT commands (AT+QMTOPEN, AT+QMTCONN), I only get ERROR or +QMTOPEN: 0,2.

My questions are:

  • Does the EC21 support direct WebSocket connections (ws:// / wss://) via AT commands?
  • If not, is there any firmware version that adds WebSocket support for the EC21?

Thanks in advance.

2

LTE-WEBSOCKET-TCP BASED – AT COMMANDS_20230531.pdf (573.7 KB)

1 Like
3

I have followed the procedure described in the “LTE-WEBSOCKET-TCP BASED – AT COMMANDS” document:
opened a TCP/TLS socket, sent the WebSocket handshake, and attempted to exchange frames.

This method appears to work only for plain ws://.
In my case, the server only accepts wss:// (TLS).
On the EC21, the TLS socket (AT+QSSLOPEN) never succeeds with this server and consistently results in either a timeout or an ERROR.

Based on my investigation, the root cause may be that the EC21 does not support WebSocket framing over TLS.

My question is:
Is there any EC21 firmware version that provides support for WebSocket over TLS (wss://)?

4

pls try to run
AT+QWSCFG=?
If it returns “error”, it indicates that the WebSocket protocol stack is not supported.