Maximum Publish Message Len

IoT Modules GSM Module
1

Hello,
I’m using mc60 module and using its mqtt stack to publish data to a mqtt broker. The datasheet does not mentions maximum publish length. Does anybody here have any idea what is the maximum length of data that can be published via a publish AT Command. The datasheet does mentions the “in-flight windows” but i do not seem to get it.

Thanks.

2

Dear Sir,
The maximum length of the publish data is 1548 bytes which already write in the MQTT application note. Thanks!

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3

Hello Kyson,
Currently I’ sending 1Kb of data to a mqtt broker in every 1 min but the module return “CME ERROR: 8508 i.e.
The length of transmitted data exceeds that of remaining transmitted buffer”
what does this actually means? From my understanding there is still some data from the previous publish request in the module tx buffer. Please correct me if I’m wrong.
Thanks.

4

Dear Sir,
You can try to send the next package data after receive the URC “+QMTPUB:0,0,0” to indicate the data have send successful. Thanks!

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5

Hello Kyson,
I do check the response URC after every publish to evaluate the success of the function. But my question is what actually causes the module to give “CME ERROR: 8508" while publishing as whatever that’s written in datasheet is not quite clear to me.

Thanks
Altamash.

6

Dear Sir,
Please check the following explanation about CME ERROR 8508.

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So please check whether each package data to send successful with URC information, and you can change the data send internal from 1 min to 5 min or 10 min to have a try. Thanks!