The QJ71E71-100 is a Mitsubishi communication module. It is designed to facilitate communication between the Mitsubishi PLC (Programmable Logic Controller) system and other devices or networks. The module supports various communication protocols such as Ethernet, RS-232, and RS-485, allowing the PLC to communicate with external devices such as computers, HMI (Human-Machine Interface) panels, or other automation equipment. The QJ71E71-100 module provides a convenient and reliable way to connect the Mitsubishi PLC system to a network or interface with external devices.