delphi and USB-GPIB Adaptor

Hi,

I have experiment with "Agilent 33220A 20 MHz Waveform Generator" and computer using USB-GPIB Adaptor.

I need to use Borland  Delphi 7 to read data from 33220a.

How can I do this?

I need .dll, but I don't have. Where can i download?

I thank any information.
Acosta.