[nomel]

No, I'm talking about the physical layer of the OSI model, and including the mechanical connections between those physical interfaces. You're talking about the link layer.

Unless your backbone/computer has a wireless hop, a literal, uninterrupted, physical chain of physical electronic devices, physically connected to one another with wires/cables, goes from my keyboard to yours. This is literal, not poetic. I'm not saying a galvanic connection. I'm saying a physical connection where, if nothing was bolted down, and high tension cables were used, I could pull and you would feel it.

[Izkata]

AT&T had wireless microwave towers for phones and tv, so I imagine there was a period near the end if its life where some dial-up connections weren't physically connected:

https://99percentinvisible.org/article/vintage-skynet-atts-a...

[DragonL80]

Working for a Midwest dialup isp in the early 2000s, we definitely served some of our smaller POPs with PTP wireless backbones, thanks in part to vast expanses of flat land with fairly tall structures dotted throughout.