Multicast Communication (Multicast) - Ebyte E52-400/900NW22S User Manual

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7.3 Multicast communication (Multicast)

Multicast (multicast) communication method requires group management of target modules in advance. All target
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modules need to be grouped in advance using "AT+GROUP_ADD=<group>".
<group> can be understood as a public address, and each module can set up to 8 group addresses.
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In multicast mode, routing needs to be re-established every time. It is recommended that the interval between
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consecutive multicast initiations be about 5 seconds.
"AT+GROUP_DEL=<group>" can delete the group address with the public address group and save the new group

information to Flash.
"AT+GROUP_CLR=1" can clear all group addresses and also clear the group information in Flash.
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The routing table can be queried through the "AT+ROUTER_CLR=?" command.
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The data frame header can be closed using the "AT+HEAD=0" command.
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The user data cannot be an internal AT command of the module, otherwise it will be recognized by the module as an

AT command, resulting in the inability to send user data.
The basic operation steps of multicast (multicast) are as follows:
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Step 1: Use "AT+GROUP_ADD=123" for module B in advance to set the group;
Step 2: Module A uses the "AT+OPTION=2,0" command to change the communication mode to multicast mode
(Multicast);
Step 3: Module A uses the "AT+DST_ADDR=123,0" command to change the communication mode to multicast
mode and set the target group address;
Step 4: Module A sends user data 1234567890. If the transmission is successful, SUCCESS will be returned; if the
transmission fails, NO ROUTE or NO ACK will be returned. NO ROUTE means that the route establishment failed; NO
ACK means that the route was established successfully but no response was received. If NO ACK occurs three times, the
routing table needs to be re-established.
Step 5: Module B receives the (ASCII code) 1234567890 sent from module A and converts it into HEX format as
31 32 33 34 35 36 37 38 39 30 (showing different encoding), and adds additional data frame headers.
The time for first initiating a unicast request is different under different airspeeds, which is at least 1.5 routing

request timeouts:
It takes about 4 seconds to initiate a unicast request for the first time at 62.5K airspeed.
It takes about 8 seconds to initiate a unicast request for the first time at 21.875K airspeed.
It takes about 25 seconds to initiate a unicast request for the first time at 7K airspeed.
Figure 8.2.1 Unicast communication
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E52-400/900NW22S User Manual