“Arduino Nano RS485 shield will help you to transmit and receive serial data using the twisted pair RS485 network. The module provides half-duplex communication. LED D1 indicates receive data, D2 Transmit LED, J1 jumper is optional and not in use in this application. DI/RE connected to D2 of Arduino digital pin which enables Receiver Output /Driver Output. CN1 connecter supply input, CN2 3 pin screw terminal helps to connected twisted pair cable. The unit can communicate over 4000 feet of 26AWG twisted-pair wire at 110 kHz into 120Ω loads.”