Possible causes of 4G drop

Question：4G invalid

Check whether 4G drops occasionally or all the time?

Pull out the SIM card in the MDVR and insert it into the mobile phone to confirm whether there is still communication traffic

Check whether the 4G antenna is firmly plugged into the MDVR；

Insert the 4G antenna that works normally on other MDVR into this MDVR；

Put the MDVR 4G antenna in an outdoor open place and check the signal strength；

Open the mdvr shell and replace it with a good 4G feeder line. The feeder line may have poor contact；

4G module damaged.Open the mdvr shell and replace the 4G modules working normally on other mdvr into this mdvr.

问题：4G掉线

确定是偶尔掉线，还是一直掉线？

把MDVR里面的SIM卡拔出，然后插入手机，确认是否还有通讯流量

检查4G天线有没插紧；

把其他MDVR上面确认好的4G天线换到这台MDVR上面；

把MDVR 4G天线放到室外空旷处，查看信号；

打开机器外壳，换一根好的4G馈线，可能馈线接触不良；

4G模块损坏。打开MDVR外壳，把其他MDVR上面确认好的4G模块换到这台MDVR上面。