This FAQ is about the socket communication without data Interaction of USR-G781.
Check if there is a serial port update in the device manager of the computer by unplugging the serial port to USB cable, and confirm whether the opened serial port cable is correct. Replace the serial cable and test again.
The parameters of the opened serial port must be consistent with the serial port parameters of the device. The factory defaults of the serial port parameters are 115200, NONE, 8, and 1. If you have changed the serial port parameters but don't remember, you can try to log in to the built-in web page to confirm.
The LAN port is connected to the computer through a network cable. Enter the gateway address in the browser to enter the built-in web page and confirm the current serial port parameters.
If it is not convenient to confirm, you can press and hold the “Reload” button 6S on the device to restore the device to factory settings.
Turn off the extra network cards of the computer, and keep only the network cards related to G781; turn off the firewall and antivirus software.
When the computer is directly connected to the LAN port of G781, if it is set to a static IP, check whether the parameters are correct. If it is set to obtain IP dynamically, check if the computer has obtained IP.
If the computer and G781 are all connected to a router, check whether the IP of the WAN port of the G781 and the IP of the LAN port conflict, and whether the computer and the G781 can ping each other.
If G781 works as TCP Client and computer works as TCP Server, check if the IP and port of the target server set in G781 correspond to the computer.
If G781 works as TCP Server and the computer works as TCP Client, check if the target server and port set in the computer correspond to G781.