1、Self Recovering Fuse Feature: USB to TTL serial port module with self recovery fuse, it can effectively protect your downloader and computer USB port in case of accidental short circuit. 2、3 Indicator Lights: USB to TTL serial port module comes with 3 indicator lights, power indicator, data receiving indicator, data sending indicator. Its working status is clear. 3、Powerful Chip: The chip integrates a USB2.0 full speed function controller, USB transceiver, crystal oscillator, EEPROM, and asynchronous serial data bus (UART). It supports full function modem signals, eliminating the need for any external USB devices. 4、Simulated COM Port: The USB to TTL serial port module works similarly to other USB UART conversion circuits. It simulates the PC's USB port as a COM port through the driver to achieve expansion purposes. 5、Supported Operating Systems: USB to TTL serial port module is compatible for Win 98 Me 2000 XP 7, for OS X 9 for OS X, for X Win CE, for Linux 2.40 or higher versions. Item Type: USB to TTL Serial Port Module Material: PCB Supported Operating Systems: for Win 98 Me 2000 XP/7, for OS X 9 for OS X, for X-Win CE, for Linux 2.40 or Higher Versions Interface: USB A 1 x USB to TTL Serial Port Module 1 x Line 1 x User Manual