Ebyte E840-DTU User Manual page 12

4G/LTE Serial Server
a) AT mode：under this mode all UART data is considered as AT command.
b) Mode switch，In the transparent transmission mode, after the serial port receives the "+++" frame data, the RX pin receives any AT command within 3
seconds, and the mode switches to the AT mode. In AT mode, send AT+EXAT<CR><LF> to switch to transparent transmission mode.
2、Network function
a) Short connection: In TCP Client mode, the short connection function is enabled. If there is no data reception in the serial port or network port
within the set time, the network connection will be automatically disconnected. The short connection function is turned off by default. The connection
time can be set from 2 to 255 seconds. When set to 0, the short connection function is disabled.
b) Registration package: The registration package is closed by default. The user can configure 4 types of registration packages. You can choose to
send the physical address (IMEI code) when connecting, send custom data when connecting, add the physics before the connection and each packet
of data. Custom data is added to the address, connection time, and data before each packet. The maximum length of the custom registration packet is
40 bytes (when set to HEX format, the maximum length is 20 bytes).
c) Heartbeat packet: In the idle state of network communication, the heartbeat packet is used for network state maintenance. The heartbeat
period can be set from 0 to 65535 seconds, and the maximum length of the heartbeat packet is 40 bytes (when set to HEX format, the maximum
length is 20 bytes). Supports two heartbeat types: network heartbeat and serial heartbeat. When the network heartbeat is selected, the communication
idle time starts, and the heartbeat data packet is sent to the server according to the configured heartbeat period. Select the serial port heartbeat, start
timing with communication idle, and send heartbeat packets to the serial port according to the configured heartbeat period.
Clear the cache: Before the connection to the server is established, the data received by the serial port will be cached. When the connection
with the server is established, you can choose whether to clear the cached data. By default, the cache is cleared. The maximum size of each Socket in
the local cache is 128 bytes, and each Socket buffer is independent of each other.
3. Enable Ebyte IoT platform function
The AT+EBTIOT command is used to set whether the module enables the transparent transmission function of the EBYTE cloud platform, after it is turned
on, the information such as the heartbeat and registration packet configured by the user will be invalid. The user only needs to set the forwarding relationship
of the corresponding device to the platform to implement the device. Data is transparent. For details of the related operations, please refer to the "Ebyte
Cloud Platform Transparent Transmission Guide".
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E840-DTU（4G-01）User Manual