Thread by @TubeTimeUS

you've never seen this D-sub connector before! it is a 36W4.

the big pins can be solid (for power), coaxial, or even high voltage (with a protective plastic sleeve).

or maybe you only need three power pins, but with the middle one of the opposite polarity

not to be confused with the classic 13W3 used on some workstation graphics cards. everyone's seen these

my personal favorite is this 3-pin D-sub (E shell, so DE-3). what plugs into it...?

why, this little screw terminal block!

here's a high voltage contact for a combo-D connector. it just fits right where the power or coax connection would go.

and if you really want to get fancy, there are even pneumatic inserts! yes, you can have an air line in with your power, high voltage, and high frequency signal. 😂

someone's even doing micro fluidics through a D-sub connector (not a commercial product but still pretty cool)

if you want a little background on where D-sub connectors came from, i looked into it a while back.

more generally, connectors that pass more than just electricity are called "hybrid connectors" and are commonly used for industrial and medical equipment. this connector has 6 pins and the blood flows in the center tube. or water, or whatever, but i got your attention, didn't i?

the industrial hybrid connectors are usually larger and involve more metal, typically looking like this

that one can handle pretty much anything you can think of in any combination. needless to say these are not cheap connectors.