Midiman USB to Midi will not connect

I purchased a new iMac yesterday and tried to attach an old Midiman USB/Midi 2x2 converter to the iMac. As best I can tell, the iMac does not recognize the USB device. This USB cable and device work fine on a PC. Any ideas what may be wrong? This Midiman may be USB 1.0. Does the iMac only recognize USB 2.0 devices?

Best,
Christopher