Precautions - Ebyte E842-DTU User Manual

Chengdu Yiyit Electronic Technology Co., Ltd

5. Precautions

The first Socket of this module is always open. After successful initialization, it will automatically establish a connection
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with the configured network server.
After the module is powered on, it has not been able to initialize successfully, that is, there is no indication on the State
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indicator for more than 30 seconds. At this time, check whether the module is installed normally, whether the SIM card is
inserted normally, and whether the SIM has failed.
The short connection function can be used to reduce the connection pressure of multiple devices to the server. When the
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short connection function is enabled, when there is no data on the network or serial port for longer than the short connection
setting period, the module will actively disconnect the connection. After disconnection, the network cannot send data. The local
serial port sends valid data, and the module will immediately communicate with The server establishes a connection. If the local
cache clear function is turned off at this time, the data packet will be cached (maximum 10K bytes). After the connection is
successful, the data will be sent to the server. If the local cache clear function is enabled, The packet will be discarded.
The heartbeat function is used to maintain the connection after the module has successfully established a connection with the
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server. In the network, if there is no data transmission for a long time after the client has successfully established a connection
with the network server, the Socket link may appear "dead", that is, the chain The path exists, but data cannot be sent or
received. Therefore, in actual use, it is recommended to enable the heartbeat packet function to ensure the reliability of the
network link.
In actual use, it is normal for the data delay difference between the two communications to be different.
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After the module closes the protocol transmission, the maximum single packet length supported by a single link is 10K bytes.
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The local serial port or network single transmission of data packets exceeding this length may cause packet abnormalities; open
the distribution protocol, each SocKet A single link packet can support up to 1024 bytes (the serial port packet length
configured by the user),
When the device serial port outputs the words "pdp error, device will be reset!", it means that the PDP context is disabled by
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the network side. It may be that the SIM card is loose or the current network channel is occupied abnormally.
The SMS function requires the inserted SIM card to support the SMS service, and the IoT card cannot send and receive SMS;
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when the device sends a SMS, the device responds OK only to indicate that the module has sent the SMS, but it does not mean
that the device has received the SMS.
After modifying the serial port frame time, the AT command also needs to be configured to operate according to this frame
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time. For example: after setting this parameter to 2000ms, the next time you power on the device to configure the device
parameters, you need to send'+++' After that, send a valid AT command within the period of more than 2000ms and less than
3000ms to enter the AT mode normally
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E842-DTU（EC03-485)User manual
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