Specifications: 485 is half-duplex communication. This transparent transmission module realizes the mutual conversion between TTL signal and RS485 signal, which can realize two-way communication, but it cannot be performed simultaneously in two directions. It must be alternately carried out in turn; that is, communication Each end of the channel can be either a transmitting end or a receiving end, but at the same time, information can only have one transmission direction. This module fully considers the lightning protection design and anti-interference design of 485 bus. When transmitting in the wild for a long distance, the "connected earth" end of the module is connected to the earth, which can play a good anti-interference and lightning protection effect, so that 485 The bus is safer; it can be connected to the earth during short-distance transmission. The standard 2.54 pitch design makes it easy for your secondary development. With a 120 ohm matching resistor, shorting R0 enables the matching resistor, and short-circuit is recommended for long-distance transmission. Support multi-machine communication, allowing access to the bus of up to 128 devices. This module can be hot swapped, and there will be no signal embolism caused by hot plugging of other 485 chips. Large area copper is provided to prevent signal interference. Note: The installation of electronic modules requires basic knowledge and requires a certain electronic professional foundation and hands-on ability. Please purchase carefully! Manual measurement, with small error. Please check size in detail before purchase. Real colors may slightly differ from the pictures, as it depends on specific monitor settings and light brightness. We highly appreciate all customers opinions to improve the selling, also if anything you unsatisfied, please contact us for probable best solution. Package Includes: 2PcsWith RXD, TXD signal indicator, the receiving and receiving status is unobstructed. It adopts a semi-hole process design with a thickness of 0.8mm, which can be easily used as a mother board or soldered terminal. It adopts imported chip, industrial grade design, super anti-interference ability, and adopts more effective 485 lightning protection design. It can be used in industrial and field harsh environments, working temperature is -40 ° C to +85 ° C, transmission Up to a kilometer (tested with 850 meters of 2*1.5 cable, it is recommended to use within 800 meters, more than 800 meters, please add repeater). Baud rate: 110~256000bps Perfect support. The 3.3V is perfectly compatible with the 5.0V power supply / 3.3V and 5.0V signals are perfectly compatible.