The only reason the Walkmans' had rubber caps was for waterproofing, not dust-proofing.
Can’t say that I’ve ever heard of dust “contaminating” headphone jacks. Is this something you’ve actually had a problem with? I suspect if it was an issue, manufacturers would have dealt with it decades ago. I have some components that are 20 years old, and the headphone jacks work fine.
How so? Just fold a tab on one end. It’ll come off and on easier than a rubber Walkman plug.Tape is so inconvenient.
Software- or relay-based, they work the same way. It starts with a normally-closed switch contact arm built into the jack that breaks connection when the plug is inserted. There is no viable work-around, other than to simply avoid breaking the connection.I know some headphone detection is software based. If I'm not mistaken, the headphone jack on my Yamaha and Integra work off a relay.
And find a way to work around the switch...