In the basement, I'll probably use some centralized high current 12V power supplies, but elsewhere I’m using 12V plug-in adapters. I ordered a couple of 12V 5A adapters. That's when the problems ...

And I've seen several 12V DC 500mA power adapters that have that output. Then I noticed something about the Input specs on these adapters which confused me a bit.

Priced around $150, the PSU is also ATX 3.1 PCIe 5.1 compliant meaning that it comes with the new 16-pin (12V-2×6) PCIe connector and bundled cable that can deliver up to 600W of power.

Seasonic's new 12V-2x6 power cables (source: Seasonic) If you've got a Seasonic ATX2 PSU, the company has 2 x 8-pin to 12V-2x6 adapter cables, which support most -- but not all -- Seasonic ATX 2.0 ...

I did something similar to an OBD-II adapter I bought for my Sony Clie (years and years ago) so that the serial port would work. The PDA didn't provide the negative voltage needed to make RS-232 work.