That's how I pronounced it. English input sounds more like Dutch "inpoet", the manual said input# was pronounced "inpoet-nummer".

(edit: long live the Internet, it's on page 135 of the manual here: https://docplayer.nl/11208014-Gebruikershandleiding-nederlan... . Nostalgia).

There is definitely a difference. If you don't hear it, you might be saying one of them incorrectly? Wiktionary has audio files for input (English) and put (Dutch) if you need a comparison. In IPA the difference is ʊ vs ʏ. In terms of describing it to a Dutch person I would say the English u is somewhere between the Dutch u and the Dutch oe sounds.

In-poot vs in-puht, roughly.