USB to RS485 rs232 to rs485 converter can be divided into the following types in terms of performance: passive 485 converter, active 485 converter, lightning protection 485 converter, optical isolation 485 converter, lightning protection and optical isolation type 485 converter.

The manufacturer of USB to RS485 rs232 to rs485 converter tells you that the passive 485 converter has the smallest size and adopts serial power stealing technology to supply power, so it does not need external power supply. Because of its small size and no power supply, it is flexible in application, but because of its small size , Many protection circuits cannot be done, resulting in poor protection of 485 devices and computers. Due to the use of serial port power stealing technology, the power supply is insufficient, resulting in a small load.
The active 485 converter just adds an external power supply to the passive 485 converter without any protection. There is basically no prospect for this type of product in the market, and this type of product is basically extinct in the market.
USB to RS485 rs232 to rs485 converter The manufacturer tells you that lightning-proof 485 converters are generally products with power supplies. The lightning protection tubes and other components can prevent external damage such as surge, electromagnetic interference, and lightning interference. Protect computers and 485 devices. There is a passive type 485 converter that claims to have lightning protection function. Because of its small size, it is not very realistic to add lightning protection tubes and other components in it. Even if there is, the performance is not very good.
USB to RS485 rs232 to rs485 converter The manufacturer tells you that the optically isolated 485 converters all use an external power supply. Among them, it is divided into single-ended isolation and double-ended isolation. Single-ended optical isolation is the use of an optical isolation chip on the 485 signal channel to convert the electrical signal into an optical signal, and then convert the optical signal into an electrical signal. There is no electrical contact on the signal path, thus realizing isolation. The double-ended isolation is based on the realization of photoelectric isolation on the 485 signal, and then the power supply of the 485 converter, using a transformer between the 232 end and the 485 end, so that the power supply has no electrical contact, thus realizing the true meaning Isolation.
USB to RS485 rs232 to rs485 converter The manufacturer tells you that the lightning protection optically isolated 485 converter is based on the optically isolated 485 converter with lightning protection function.