Long-distance connection scheme between computer and scrambler 

Schematic diagram of the long-distance line connection between the computer and the scrambler of the Tonghui descrambling system:

① Connect STM485S to the COM port (serial port) of the computer.

    STM8500S is connected to the communication port of the scrambler (232 port).

    The distance can reach 1.2Km long.

② STM485S and STM8500S are connected by two wires, DA+ is connected with DA+, and DB- is connected with DB-. It cannot be connected to other terminals, nor can it be cross-connected.

③ Special attention: Do not plug or unplug when power is on!

The scrambler and the computer are respectively connected to the ground wire to prevent lightning and static electricity interference.