RC76 CME Error 923

IoT Modules Legacy HL Series
1

I am receiving a CME Error 923 from a RC7620 modem without a clear indication of any issue:

Tx: AT+COPS?
Rx: +COPS: 0,0,“Optus AU IoT eSim”,2
Rx: OK
Tx: AT+KTCPCFG=1,0,“a valid internet address”,10113
Rx: +KTCPCFG: 1
Rx: OK
Tx: AT+KTCPCNX=1
Rx: OK
Rx: +KCNX_IND: 1,4,1
Rx: +KCNX_IND: 1,1,0
Tx: AT+KTCPSND=1,28
Rx: +CME ERROR: 923

The “+KCNX_IND: 1,1,0” states the socket is connected, however any attempt to send data results in a 923 error (Error due to invalid state of terminate port data mode).

What is the issue here and how can I work around it?

2

didn’t you need to wait for the “+KTCP_IND: 1,1”?

3

Where is this documented? The documentation states:

Notification format:
• For = 0 or 1:
+KCNX_IND: < cnx_cnf >,< status >,< af >

The indicator is supposed to have 3 parts? So can I assume the socket is not connected until “+KCNX_IND=1,1” is received?

4

I guess +KCNX_IND is for IP layer
for TCP layer, you need to wait for +KTCP_IND

5

OK thanks.

Is there a whitepaper or application note describing the correct sequence of AT commands to bring up a TCP connection?

6

In HL78xx AT command guide, there is some example in Appendix section, i think you can regard that part as reference

Of course for the official explanation, you need to refer to the AT command of RC76