Right. The hard line on this comes from aerospace. If A won't connect to B, you check the spec. If A isn't compliant with the spec, A is wrong and the vendor of A has to fix it. Same for B. If you can't tell who's wrong from the spec, the spec is wrong. This is why you can unplug a Pratt and Whitney engine from a aircraft and plug in a Rolls-Royce engine.

Now, this worked a lot better when aerospace companies and the USAF had real clout with manufacturers. If it wasn't in compliance with the spec, you put a red tag on it and rejected it. The supplier didn't get paid.

The way it works today is that if the supplier is bigger than you are, it's your problem.