(1) Compatible with 3.3V and 5.0V power supply.(2) Compatible with 3.3V and 5.0V signal.(3) Absolute using imported chips,industrial design,anti-interference ability,while using more effective mine design can be used in the industrial field and harsh field environments,the working temperature of -40-85'C,transmission distance up to 1 kilometer (made with 850 meters of cable F1.5 tests recommended in the 800 meters,more than 800m,please add repeaters).(4) Semi-hole pads,onboard module,thin PCB,having a thickness of 0.8mm.(5) Has RXD,TXD signal indicator light,monitor send and receive status.Features:(1) The module is fully considered mine design,long-distance transmission signal 485 in the wild,the module "Connected to the ground" terminal is connected to the earth,can play a very good anti-jamming and anti-lightning effect,more secure; it can not connect with the ground when the indoor short-distance transmission.(2) Using the standard 2.54 pitch design,easy secondary development.(3) Has a 120 ohm termination resistors,shorted R0 to enable the termination resistor.(4) Support multi-machine communication,allowing access at up to 128 devices on the bus(5) The module can be hot swapped,the signal does not appear dead phenomenon.(6) A large area of copper to prevent interference.