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IoTReady / a9_gsm_gps_library

Libraries for the AI Thinker A9/A9G GSM/GPS modems.
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Character limit when doing publishing through MQTT #14

Open louistaannn opened 3 years ago

louistaannn commented 3 years ago

I would like to ask if this A9G module has a character limit when doing publishing though MQTT. I tried publishing the word "test" and it worked fine (it showed up in the broker). Then, when I publish some string with length 512 chars, the A9G module delays for a while (I guess about 40 seconds) and gives the response "OK". However, it does not show up in the broker. How can I fix this issue? Thanks

tejpochiraju commented 3 years ago

@KaranRajPradhan - could you help out @louistaannn

KaranRajPradhan commented 3 years ago

@louistaannn - Are you using AT commands or a custom firmware for the A9G?

We haven't come across such issues with publishing messages due to their message size. The MQTT protocol allows up to a maximum message size of about 260MB which however is most definitely restricted by brokers to different sizes. For example, AWS IoT limits this to 128KB in size.

Your problem could actually be the broker configuration limiting your packet size. What broker are you using?