This diagram shows me connections to Vcc (power in), ground, and a signal line that is ALWAYS > 0V.
You have a salesman protecting your dependence on him by keeping between you and what you need to know.
You might want to impress on the Jerk that if you can't get real docs for the part you have, it will be time to find a supplier who can. Look some up, when he "calls your bluff" you can deflate that balloon by pulling out a list of > 1 competitor/supplier.
But if you're happy with it taking How Long to get simple information, if you think that's okay then smile and be nice, maybe you'll get dinner and flowers or at least a movie out of it.