My aging 2015 car has one big problem: it doesn't have Android Auto or Apple CarPlay. I didn't really mind, as I could always connect my smartphone to the in-car audio using a cheap USB-C to 3.5mm adapter to keep the music playing, no matter what. That is, until I noticed that more and more of my smartphones were failing to work with my good old adapter. Everything worked fine when I used a Nothing Phone 1, but with the Samsung Z Fold 8? It doesn't want to know. A $20 adapter solved my problems overnight, and my wonderful Car Music playlist booms out wherever I drive once more — but why did the USB-C to 3.5mm jack adapter stop working to begin with? Why your USB-C to 3.5mm jack adapter doesn't work Well, not with the latest smartphones The dreaded "USB device message not supported" isn't entirely new; Samsung users began reporting this issue back in 2020 with the Galaxy S20, and that wasn't the only phone flashing this message. But I'd been somehow getting away with the problem for years, not just on my beloved Nothing Phone 1, but a whole host of smartphones across that period. The problem is mixed: it's a phone problem, for sure, but it's also an adapter problem. In part, it starts because all USB-C to 3.5mm adapters and conversion cables look essentially the same from the outside: a plug at each end, wire between, and a tiny DAC somewhere in the process converting the digital signal into analog. But in some cases, the cheap ones are passive, requiring the phone's USB-C port to recognize the adapter's resistor configuration and support USB-C's Audio Adapter Accessory Mode. When it does, the phone routes analog audio through the USB-C connector. So, when the handshake does