SIIG’s 4-Port USB to RS-232 Serial Adapter Hub is designed to add 4 RS-232 (9-pin) serial ports to your USB-enabled desktop or notebook computer. It supports serial port data transfer rate up to 230Kb/s, and is powered by the USB bus, no external power adapter is needed. With support for USB plug-n-play, simply plug this serial adapter hub into via any available USB port and instantly add 4 additional RS-232 serial ports to your computer. It is the perfect solution for connecting additional RS-232 serial devices such as modems, digital cameras, ISDN terminal adapters, graphics tablets, PDAs, bar code scanners, label printers and more.