Add 2 serial rs 232 ports to any laptop or computer with a usb portr r simple installation and operation provides robust serial connectivity to legacy pcsr drawing power from the usb bus saves the hassle of carrying an external power adapter for this add on serial portr extensive list of compatible operating systems makes this device perfect for almost any rs232 applicationr r the startechcom icusb232c2 2 port usb to db9 rs232 serial adapter cable lets you connect up to two db9 rs232 serial dev