3 LEDs for indicating the power and transceiver status. High quality USB-B and RS232 connectors, smoothly plug/pull. Industrial grade metal case, supports wall-mount and rail-mount installations, solid and beautiful, easy to install. Fully automatic transceiver circuit with no delay, ensures the USB port communicates with different interfaces fastly and stably, without interfering with each other. Onboard TTL serial 3.3V/5V voltage translator, config the TTL level via switch. Onboard TVS (Transient Voltage Suppressor), effectively suppress surge voltage and transient spike voltage in the circuit, lightningproof & ESD protection. Onboard self-recovery fuse and protection diodes, ensures the current/voltage stable outputs, provides over-current/over-voltage proof, improves shock resistance. Onboard unibody power supply isolation, provides stable isolated voltage, needs no extra power supply for the isolated terminal. Onboard unibody digital isolation, allows signal isolation, high reliability, strong anti-interference, low power consumption. Adopt original FT232RNL chip, fast communicating, stable and reliable, better compatibility. Supports multiple communication interface conversion: USB to RS232, USB to RS485, USB to RS422, USB to TTL.