Generally speaking, when the user sets the parameters of the Modem and enters the serialnet mode, the Modem will automatically remember all the current States and parameters, and will not lose them even if there is a power failure. In addition, Modem has the function of redialing after disconnection. This makes the Modem like a transparent transmission channel, as long as the user provides a stable power supply, there should be no problem. However, in practical engineering applications, users also put forward higher requirements.For example, there is no problem in continuous unmanned work for many years, and communication lines are always kept open. Therefore, the following recommendations are made for Modem users.

  1) Use the Modem reset pin or the short switch power-off reset function. In view of the uncertainty of wireless communication and the high reliability requirements of users, it is suggested that users add this part of the circuit to ensure that there is no mistake.

  2) Many users mentioned how to detect an open circuit on a communication line in Serialnet mode. The products of some companies detect by sending heartbeat data. In order to ensure the transparency of the user channel, there must be a DLL link library in the center. We believe that this method is not ideal. The presence of the DLL adds a link to the data. The central node of unix and Linux platform has professional link interface, but also has certain security risks and unstable factors.Our product is to open the standard socket interface directly to the user, and almost all programmers can easily implement data sending and receiving functions on different platforms. I think the function of heartbeat package is suitable for solving in the application layer, which can be closely integrated with the user's application program and reasonably reduce the data flow.

  4G Modem：

  When the user is in socket mode, the disconnection of the monitoring data link can be detected by heartbeat packets or pings. When the heartbeat monitoring finds a problem, it can be solved by resetting.

  What are the features of 4G Modem? The amount of communication data is large:

  4G provides customers with high-speed Internet access and wireless data connectivity at speeds up to 100Mbps downstream and 50Mbps upstream for applications that transfer large amounts of data, such as serial camera image transfer.

  Communication is fast:

  The 4G Modem has a lower ping value than the 2G/3G module, and the module takes less time to send data packets, which is suitable for applications requiring high response speed, such as remote alarms.

  Good compatibility:

  4G Modem supports not only FDDLTE/TD-LTE but also TD-SCDMA/WCDMA/EDGE/GPRS/GSM/CDMA1X/EVDO modes.