[zdragnar]

The Amish I have visited were as a sibling commenter to you describes: a single diesel motor runs the compressor. Ostensibly, a person with a bike, hand crank or horse on a treadmill could do the same, albeit extremely slowly. It is considered a minor compromise that doesn't have too significant an effect to be avoided.

I believe some also had mechanical windmills, though none for electrical generation. The area wasn't suitable for waterwheels- if it was, I suspect they may have forgone the diesel engine.

This group also had single landline phone in the community, in someone's yard nearish the road. They used it for the rare cases where letters weren't practical- things like calling a doctor, etc.

Keep in mind, the limitations are based on how a thing affects your relationship with God and each other. Buttons on clothes, for example, weren't a thing; they were seen as a vanity (often too decorative). Instead, safety pins were the norm. As such, technology isn't banned for being technology, but as part of a larger category of things that draw you away from devotion- be it pride, vanity, etc.