3a and USB

[ROCCO]

I've an old Psion 3a (I love it), an hold cable 3link (adb) to connect Psion to my Imac and the old Software Psion link.
Using Imac (USB port) with Entrega or Keyspan adapter (usb adb) I can'set in Psion link the USB port. What I can do?
Thk all
Rocco