What do you mean 485 was approved?

Approval means approval. 485 usually refers to RS-485 protocol, which is the standard of serial communication.

1 and 485 communication protocols are the standards of serial communication. The voltage and impedance have been defined, but the software protocol has not.

2. The bus standard stipulates the electrical characteristic standard of the bus interface, that is, the definition of two logic states: the positive level is between +2V and +6V, which indicates a logic state.

3. A negative level between-2V and -6V indicates another logic state; Digital signal adopts differential transmission mode, which can effectively reduce the interference of noise signal. 485 industrial bus standard can effectively support multiple sub-nodes, with long communication distance and high sensitivity to information reception.