getting matlab to locate USB ports


Are there any functions in any version of psychtoolbox that enable
matlab to locate and/or recognize a device plugged into a usb port
(mac or pc)? We are attempting to sync an eye-tracker with a
program running in matlab and the info stream from the eye-tracker
would be coming in through USB preferrably though possibly serial.
Any information on this subject would be greatly appreciated.

thank you,