This product is fully compatible with Raspberry Pi 4 (1GB, 2GB,4GB) and hopes you enjoy hacking with Pi 4 and all of other Pi 4 accessories.
RS-485 is a cost-effective solution in serial communication networks. It can be used up to data rates at 10 Mbit/s or distances up to 1200m at lower speeds. This RS-485 Shield is a standard add-on board for Raspberry Pi. It is integrated with simple screw terminal as well as DB9 interface.
This module do not contain a Raspberry Pi, if you need one please check here
RS-485 Shield for Raspberry Pi Eagle Files
Python Test Code
PDF Format Wiki