Original CH344L Chip Adopts original CH344L chip for fast communication, stable and reliable performance, and better compatibility.; USB to 4-Ch Isolated RS485 Supports USB to 4-channel isolated RS485, convenient for expanding multiple RS485 industrial serial devices.; Power & Digital Isolation Onboard unibody power supply isolation and digital isolation, providing stable isolated voltage with no extra power supply needed for the isolated terminal.; Comprehensive Protection Circuits Onboard TVS, self-recovery fuse, and protection diodes for surge, ESD, over-current, and over-voltage protection.; Industrial Metal Case & 120R Resistors Onboard 120R termination resistors enabled/disabled via DIP switch; industrial metal case supports wall-mount and rail-mount installation.