There are two methods for Cellular Modem point to point transmission
APN internal network special card (APN configuration location as below)
2. Server forwarding
Open transfer.txt file in central forwarding software folder, then fill in two devices you need to use to transmit data. ID number is as below (the former is transmitter side, the latter is receiver side).
Then open vc_demo.exe software, set port number and wait two devices online (as shown below)