I decided to follow suit and buy a similar adaptor off eBay too. It arrived all ok, and I just tested it out with my HP 8924C using the supplied Agilent Interactive IO software, and it works as expected. I can query it and get a valid response. I also tested it on my HP 8901B modulation analyzer and it worked perfectly too - I must admit it was kinda neat interfacing to a piece of equipment designed and first manufactured in the 1970's, using a USB interface running on a relatively modern computer!
Next step is to get it all working with linux-gpib (like FrankBuss did) and using the Python bindings, write some code to automate some test procedures that I occasionally do.
Nice, is this using the VISA framework? Then you might be able to use it from Windows and Python with something like this. But using it from a small Linux system like the Raspberry Pi has the advantage that you can do long measurements or build test jigs, without the need to run a PC all the time.
Luckily I have a couple of Pi Zeros lying around - the older non-wireless type - so I can dedicate one to the task, kinda like giving the instrument a dedicated interface.
I don't think the 8924C supports VISA, but I'm not really sure what VISA is and how it works. Modern test equipment certainly has come such a long way, with VISA, LXI, Ethernet and USB all included these days.
In any case I can just send the raw ASCII GPIB commands to the unit and request a response, so that's a start.
What does the VISA framework add?
Also, since I have two instruments with GPIB, I am tossing up whether or not to buy a second USB-GPIB adaptor or use a cable to put both devices on the one bus...
Decisions, decisions!