If you keep calling it DB9 everybody knows what you're talking about. They don't think you're weird and they also don't waste time talking about terminology.
Words mean things. Especially in engineering disciplines.
It's perfectly fine for a product manager to say "DB9", but the guy who has to order the part from a supplier will probably want to use the correct terminology. If there's a mistake, it's the supplier's fault.
I struggle with someone I work with because of this :( They might as well call a DB9/DE9 a USB connector and expect everyone to understand them. They're both connectors after all, right?
And this reminds me of the time that my colleague put DB15 on a whole bunch of drawings, and we ended up with DA15 connectors instead of DE15. If I see DB9 on any drawing that comes across my desk, it will be corrected.
