Simultaneously connect four RS-232 serial devices to your USB ready PC or Mac Supports standard serial devices USB 1.1 Compliant Easy plug and play installation Connectors: USB A Male to 4 x 9 Way D Serial Male Supports remote wake up and power management Data buffers for upstream and downstream on each port Powered from USB Bus with no external power supply required Compatible with Windows 98/ME/2000/XP/Vista/7 (32 & 64 Bit), Mac OS 10.4 - 10.6 and Linux Warranty: 2 years