This 2 Port USB to RS232 Serial DB9 Adapter Cable lets you connect two RS232 serial devices to your Mac or PC laptop or desktop computer through a single USB port, as though the computer offered built-on DB9M serial connectors.The USB/RS232 Serial DB9 Adapter Cable is compactly designed to preserve valuable workspace, and is bus-powered to eliminate the need for an external power adapter.A cost-effective solution that bridges the compatibility gap between modern USB-capable computers and legacy RS232 serial peripherals, this dependable USB/RS232 Serial Adapter cable is backed by StarTech.coms 1-year Warranty.