Waveshare RS485 TO ETH Manual page 31

485 TO ETH (B) User Manual
Figure 34 MQTT advanced parameter configuration
Described as follows:
1 Protocol version: The current mainstream is version 3.1.1, if you need to choose version
3.1, please choose here.
2 Keep-alive time: The heartbeat time of MQTT, the minimum is 10 seconds, and the
default is 60 seconds.
3 Server clear subscription: Whether the server clears the subscription information after
the client is disconnected.
4 Whether to enable the last wish: whether there is a last wish.
5 Last wish theme: Last wish theme.
6 Last will information: information about the last will.
7 Whether to save the last wish: whether the server needs to keep the last wish message
sent to the client when the client is abnormally offline.
8 Last wish quality: the delivery quality level of the last wish message sent by the server.
9 Subscription quality: The delivery quality level of the subscription. In some cases, it
needs to be set to 0 to prevent disconnection caused by retransmission.
10 Publish quality: The delivery quality level of the message published by the client. In
some cases, it needs to be set to 0 to prevent disconnection caused by retransmission.
11 Whether to save the publication: whether the server keeps the last message (if there is
a new client subscription, it will be sent to the client)
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