Feature: 4 Port RS232: The USB to serial adapter has a 4 port RS232 for controlling multiple devices, easily allowing you to connect RS 232 devices directly to your laptop via the USB port. COM Reserve Feature: For added convenience, the USB to serial adapter Hub has a COM reserve feature, so COM port assignments are preserved across reboots. Compact Design: COM serial port cards feature a small design and are powered by USB, eliminating the need for bulky power adapters or sockets. Compatible System: USB to serial adapter hub supports various systems, such as for XP,for Vista,for 10 8 7 (32/64 bit) ,for ,for OS X, etc. Wide Compatibility: USB to RS232 adapter is ideal for laptops, routers, GPS, programming machines, printers, scanners, modems, digital cameras, PDAs, etc. Specification: Item Type: USB to Serial Adapter Product Material: ABS Interface:4 x RS232 Interface,1 x USB Interface Compatible System:For Xp,for vista,for 10 8 7 (32/64 Bit) ,for ,for OS X Etc. Package List: 1 x USB to Serial Adapter 1 x USB Data Cable How to use: