I'm having a time with USB HID stripe readers and ...

getusbdevicelistasstring
usbdeviceindex

GetUSBDeviceList doesn't work with VFP. Have to use GetUSBDeviceListAsString which seems to lock up VFP if run more than once in the same session. I'm also having trouble with a USB HID Mag Stripe reader. Or rather SIM is having trouble with the reader. One time it works, next time it doesn't or randomly drops characters from the card stripe. Verifone is researching and may have an update.